China is currently undergoing a profound transformation in its demographic development, characterized by very low fertility rate,rapid ageing, and negative population growth. These demographic shifts have significantly reshaped the interaction between population and socioeconomic systems in the country. In this context, forecasting future population trends constitutes a critical prerequisite for understanding future population dynamics and addressing its impacts on socioeconomic development. Existing research on China's future population trends has predominantly focused on national-level analyses, with little attention paid to regional disparities between urban and rural areas. Using the latest data from the National Bureau of Statistics of China, this study employs the Cohort Component Method to simulate population trends both at the national and urban-rural levels from 2025 to 2100.

To capture the range of possible future population trajectories under varying fertility regimes, three scenarios are established. In the low scenario, fertility would continue to drop to extremely low level at 0.75 by 2035, while fertility would slowly rise to higher levels at 1.3 and 1.6 respectively by 2050 in the context of varying degrees of fertility policy incentives under medium and high scenarios. Results indicate that China's population will continue to shrink throughout the 21st century, declining to 1.18-1.28 billion by 2050, falling below 1 billion between 2063 and 2078, and further decreasing to 0.45-0.80 billion by 2100. The number of annual births in China is expected to follow a downward trajectory throughout the 21st century. Although a recovery in women's fertility rate may drive a fluctuating rebound in birth numbers, the long-term downward trend is unlikely to be altered due to the substantial challenges and limited potential for increasing fertility rate, as well as the ongoing reduction in the number of women of childbearing age. Moreover, fluctuations in the births will affect the size of school-age population through cohort transmission. Projections suggest that China's school-age population will experience a sharp reduction over the next 15 years, with substantial implications for the allocation of educational resources. Additionally, while the size and share of the working-age population aged 15-64 will fluctuate slightly, both are expected to trend downward during this century. Meanwhile, China will witness an acceleration in its population ageing. The proportion of elderly population aged 65 and above is projected to exceed 30% in the mid-to-late 2040s. By then, the size of elderly population will exceed 380 million, making China the country with the largest elderly population in the world.

The findings also highlight an increasing divergence between urban and rural population. The urban population is expected to continue growing over the next decade, remaining above 940 million until 2050, while the rural population will maintain a sustained shrinking trend throughout the century. Both urban and rural areas will experience a notable decline in the child population aged 0-14 within the next five years, with a reduction of approximately one-fifth in urban areas and around two-fifths in rural areas. The ageing process in rural areas is ahead of that in urban areas, although the urban elderly population will have a longer growth period and a higher peak value.

Due to disparities in national realities and linguistic systems between China and the West, the introduction and application of demographic indicators borrowed from Western scholarship often suffer from problems such as mechanical adoption and inconsistencies between name and substance. These problems are mainly manifested in literal translation, conceptual over-generalization, inconsistent indicator terminology, and discrepancies between indicator names and their computational definitions. A typical example is the term “Infant Mortality Rate”, which has long been rendered in Chinese as “婴儿死亡率”. However, this translation is misleading. By tracing the historical development of “Infant Mortality Rate” and examining the original expressions in English-language demographic literature, we find that terms denoting similar mortality indicators are strictly differentiated in wording when referring to “rates” or “probabilities”, and that all major computational approaches to the “Infant Mortality Rate” adhere to the core principle of probability. However, this essential distinction has been completely obscured in its Chinese rendering. We propose that terms prone to misuse or conceptual confusion should be localized and refined in accordance with China's empirical realities. Such efforts are essential to ensuring the accuracy of classical demographic concepts and indicators in the Chinese context.

Diverging from patterns observed in developed countries, China has experienced a uniquely rapid fertility decline occurring at an earlier socioeconomic development level than would be predicted. Based on data from a special survey on groups who remain unmarried, childless, or have few children in China, this study identifies three distinctive factors contributing to China's ultra-low fertility: childcare challenges, education anxiety, and housing cost burden. Against the backdrop of a rapid “refamilialization” of caregiving responsibilities, the nurturing capacity of families has weakened while parental obligations have intensified. The intersection of traditional values emphasizing education and an intensely competitive selection system subjects parents to growing pressure and responsibilities in their children's education. Meanwhile, population concentration, unequal housing renter-owner rights, and inadequate housing security have sustained high housing costs. These factors significantly increase the financial, time, and psychological costs associated with raising children, resulting in suppressed fertility intentions. Effective pronatalist policies should remove barriers to fertility decision-making and target these three constraints unique to China's childbearing-age population.

With the growth of internet usage among older people, concerns about “older adults' internet addiction” frequently appear in media and research. To achieve a comprehensive understanding of “older adults' internet addiction”, this study discusses the concepts, phenomena, and impacts of “internet addiction”. “Internet addiction” is characterized by three features, including “excessive use”, “damage to primary activities and social functions”, and “persistent and prolonged states”. Existing discussions and studies mainly focus on the single dimension of “excessive use”, exaggerating the issue of “older adults' internet addiction”. Data from the “Survey on the Digital Divide and Integration of the Older Adults in China” show a low proportion of older people who are addicted to the Internet. Currently, the main challenge in the internet lives of older adults is how to deal with the “digital divide”. To enhance the internet accessibility and proficiency of older adults, we suggest upgrading the intelligent device hardware, software, and functions for their convenience and providing guidance on smartphone use for older people. This will help older adults benefit from the development dividends in the internet era.

China's negative population growth is an objective law of population development, with a unique transition process and development trend. In the future, long-term and rapid negative population growth may pose challenges to the economy. It is necessary to cope with negative population growth actively by establishing a fertility support policy system, improving population quality, optimizing the spatial layout of the population, raising per capita consumption, and enhancing labor productivity.

The key to accurately assessing China's fertility level lies in high-quality data. The 7th population census has obtained data of very high quality mainly due to the newly added ID number registration and application of information technology, providing a good opportunity for reassessing China's fertility level. This study shows that the total fertility rate (TFR) of China maintained above 1.6 from 2006 to 2017, exceeded 1.7 in most of the years, but dropped sharply from 2017 to 2020. The TFR was fluctuating considerably, ranging from a low of just 1.3 in 2020 to a high of 1.89 in 2012 and 1.88 in 2017, with a 15-year average of 1.7. Fertility preferences, fertility policy adjustments, and COVID-19 had marked influence on fertility level. The average number of children ever born suggests that there is still potential for improvements in China's fertility level, and the key measure is to fully eliminate the emerging fertility inhibiting factors and build a fertility/family-friendly society to tap this potential.

The 7th Population Census has achieved the lowest underreporting rate in history and is therefore a highquality census. The improved quality of the data is not only due to the great social organization and mobilization capacity of the Chinese government, but also closely related to the new measures adopted in this census, including digital data collection, additional channels for respondents to register online, matching and verifying data by using administrative records across multiple sectors, and ID number collection. The 7th Population Census reflects new “changes” in the population, which may improve the knowledge of objective facts about the population. The current population of China is characterized by “a larger total population, a higher proportion of the young and of the elderly, and a lower proportion of the working-age population”.

For thousands of years, the Chinese population has approximately been following exponential growth, with occasionally short-term exogenous decrease. In the 1990s, the intrinsic rate of natural increase turned negative, indicating the accumulation of negative population growth momentum. One quarter of prefecturelevel regions in China experienced negative population growth by 2010, as a result of population floating and migration. Population natural decrease was observed in 8% of county-level regions in China in 2010. According to the medium-variant population projection, China's population growth would become negative after 2027. The negative growth of working-age population would be much earlier and more rapidly than that of total population in the first half of this century. The older population would grow rapidly during this period. Negative population growth is not only a matter of quantity, but also of structure, which is directly affected by fertility, mortality and age structure changes. The mutually reinforcing process might happen between negative population growth and ageing. 

Some reports claim that Chinese womens infertility rate stands at around 15%, which might adversely affect the fertility rate. However, studies in different fields adopt different definitions and measurements of infertility, leading to considerable variations in prevalence estimates. The estimate (i.e. 15%) might be developed based on clinical or epidemiological definition, which does not necessarily mean that 15% of women are incapable of giving births throughout their lives. From the perspective of cohort fertility, we estimate the proportion of Chinese women aged 40-64 who have never given live births based on data from population censuses and annual sampling surveys. We argue that the proportion of women aged 40 and above reporting no live births or pregnancies has always been much lower than 15%. Universally Chinese women have given birth to at least one child by the end of their childbearing age.

Cohort-component method, the most widely used method in population projections, involves the issues of calculation and the details of programming when applied to the population projection software, which could impact the accuracy of projection results. Taking the mainstream projection software programs into account and based on the actual population data of Sweden, this paper, conducting comparative population projection tests, examines the applications of cohort-component method in the three population projection software programs including MORTPAK, Spectrum (DemProj) and PADIS-INT. The results show that the results of single-year age group obtained by the interpolation of five-year age group of the initial population are consistent and close between the three software programs; there is little difference in survival ratios calculated on the basis of the projection results of the three software programs; in the birth population projection, the three software programs don’t show great difference either. PADIS-INT has reached the projection level that international mainstream population projection software should have. Since PADIS-INT supports richer functionality especially in the parameter setting and the presentation of projection results, it is more suitable for a detailed population projection with application properties

 The implementation of the universal two-child policy will have a profound influence on China's future trends of population and changing path of aging. Using data from the 1% population sampling survey conducted by the National Bureau of Statistics in 2015，this paper conducts simulations of the size and structure of China's population over the years 2015-2100 by taking into account the potential demographic impacts of the fertility policy adjustment. The results show that China's total popula- tion will grow to the peak in around 2029 and then enter the era of negative population growth; China's population structure will be aging with shrinking working-age population size and expanding elderly population size; the speed of the decline in China's proportion of working-age population will be fast before 2050 and slow with fluctuations after 2050; China's size of elderly population will peak in around 2053 and then gradually begin declining; China will experience a rapid increase in proportion of elderly population before 2050 and the pace of population aging will slow down after 2050.

The numbers of accumulated couples and their extra births are major concerns after im- plementing the universal two-child policy．Using data from the 2014 national population sampling sur- vey，this paper，employing a population group-component calculation and projection method，provides estimates of the size of extra births that would be influenced by the two-child policy after computing the amount of accumulated couples in 2016．The results show that the number of target population under the two-child policy would be at around 91 million in 2016 among which women at age 40 and above account for 49． 6% ．Under medium fertility scenario，the size of extra births would reach around 17 mil- lion in 2017－2021 with an annual average number of 1．6－4． 7 million．Although the number of accu- mulated couples subject to the two-child policy is large，the size of their extra births would be relatively small，implying that China would have a smooth transition to the two-child policy．

Driven by decreasing fertility along with improving life expectancy，the world is entering an irreversible aging society．As a developing country with the largest population，China will be experiencing a sustained and rapid aging in the next 40 years．It is widely held that aging would inhibit the economic growth of China，leading even to recession．While the United States is also facing the aging problem，a research report prepared by the US National Academy of Sciences has reached different conclusions about the impact of aging on macro-economy．Population aging would have a significant impact on government expenditure; how- ever its impact would be very small on labor productivity，innovation and asset prices．Accumulation of private assets due to aging may even have a positive effect on the economy．Overall，the impact of aging on living standards is limited，and the overall macroeconomic impact is moderate．These views and conclusions about the relationship between aging and macro-economy have important enlightenments and implications for the related ageing studies in China．

How low is China’s recent total fertility rate? Data quality is the key to the answer． Population at ages 5 －7 from the 2015 household registration statistics is currently the latest available data which are believed to best represent the actual numbers of the 3 cohorts． Thus，estimates are highly reliable of China’s total fertility rates for 2008 to 2010 based on these data． The main conclusion is that China’s total fertility rates in 2008 － 2010 stood roughly at 1. 63 －1. 66. However，there is inevitable under －registration of the youngest age groups in the household registration data，fertility estimates provided in this paper are the lower limit of China’s actual fertility level． Thus，China’s total fertility rate in 2008，2009 and 2010 must be higher than 1．66，1．66 and 1. 63 respectively.

China has fully implemented a two-child fertility policy for couples that either side has no siblings. Meanwhile, two noticeable changes were observed in 2014. One was a noticeable fall in the sex ratio at birth, while the other was a marked increase of the number of annual births. In this context, this paper examines China’s current fertility by analyzing the effect of the new fertility policy and estimates fertility trends in the near future. Our analyses suggest that the new fertility policy has just had the effect that was previously expected, and China’s annual births would be expected to increase to nearly 18 million in 2015. China has not yet had the fertility “crisis”. With further adjustment of fertility policy, China’s fertility level still has potential to upturn and would rise to 1.7 or over in the very near future.

A fundamentally important issue in ageing societies is how to define“old age”and“elderly”people. Upon reviewing historical experience and clarifying practical requirements，this paper presents a theoretical framework of the definition of“elderly”and outlines its dynamic standard and scientific basis. Productive state，healthy state and disability-free state reflecting the different cognitive styles of“elderly”from the diverse dimensions of production and life should be taken into consideration when rethinking the definition system of“elderly”at distinct levels. With economic and social development，there is a need to redefine “elderly”from the different dimensions of production and life by constructing the productive state，healthy state and disability-free state life tables on the basis of the social surveys，making the age threshold of the elderly well-founded. Redefining“elderly”would contribute to repainting the blueprint of ageing research and reconstructing the patterns of ageing societies，enabling societies to deal with the ageing challenges more effectively.

Fertility in China dropped below the replacement level in the early 1990s, and has been increasingly lower, arousing intense academic discussion on fertility policy adjustment．This paper estimates the size of objective population that is targeted by the two-child policy after computing the amount of the only children in 2012 based on the data of the 2005 national 1% population sampling survey, and analyzes its impact on number of annual births．The results show that on account of the large number of the objective population covered by the two-child policy and women's strong desire to have the second
child，if there was an immediate transition to a universal two-child policy, number of annual births would sharply increase with the peak value up to nearly 50 million and a total fertility rate of about 4.5．However, immediately implementing the two-child policy could significantly retard the negative growth trend of population in the future, increase labor supply and slow down population aging in China．

Exploration of Chinese paths of socialist construction and demographic transition paralleled each other from 1949 to 1978.Mortality rate decreased rapidly during the early 1950s as a result of the public health campaign,which initiated the process of demographic transition in China.Countering the problem of rapid population growth in 1950s,China put forward the theory and the concept of "realizing planned childbearing",and the Chinese model of demographic transition was brewing.Orientation of the Chinese path of demographic transition was reinforced in the 1960s in the context of intensifying contradiction between population and socio-economic development.Finally,China launched the demographic transition by vigorously implementing population control and family planning in the 1970s in the midst of "Cultural Revolution" when the rapidly increasing size of population exerted great pressure on economic development.The Chinese path of demographic transition is determined by the changing characteristics of the times and China’s special national conditions.

The leaders of CPC cleared their attitudes toward family planning in 1962 and answered the question whether population-control policies should be carried out in socialist society.Since then,in the guidance of Marxist theory,according to the concrete practice of China’s population development,the leaders of CPC not only adhered to the answer that population control policies should be implemented in socialist society,but also gave creative answers to the questions about the purpose and means of population control.The population thoughts and theories,based on the answers to the questions about population control,which are the complement and enrichment of the Marxist population theory,are important components of socialist population theory and significant theoretical results of Marxism Sinicization.

This article reviews the evolution of CPC leaders’ thinking on population issues during the Period of New Democratic Revolution and Socialist Construction.People are the subjects of social activities,and hence population theory is an essential part of the Marxist Theory.It has been a great concern of the CPC to apply Marxists’ population theory to investigate China’s population issues and explore the approaches of population development in the process of carrying out socialist revolution and constructions.In the early years of the CPC,its leaders criticized the viewpoint of "the overcrowding problem",which ensured the right direction of revolution.After the success of the revolution,the CPC has correctly recognized the law of population development,creatively put forward the notion of family planning,population control and accommodating population reproduction to material production.This has not only created a favorable population circumstance for the construction of socialism,but also made important contributions to the enrichment and development of Marxist population theory.

Migrant population concentrated communities have been emerged and developed in the context of urbanization,and has become the major areas of inhabitation for the migrant population in Beijing.The number of Residential Communities accommdating migrant population over ten thousand amounted to 102 in 2000 in Beijing,accounting for 30.4% of the total number of Residential Communities and 74.4% of the total migrant population of Beijing.This situation will not change in the short term,and will result in larger scale concentrated communities with the development of Beijing.Migrant population concentrated communities can be divided into fully-depending,semi-depending and non-depending types according to the relationship with industries.In a dynamic perspective,concentrated communities of non-depending type will transform or disappear when the society implements minimum wage plan and makes upward mobility possible.However,problems surrounding the other two types of concentrated communities could only be settled by industrial restructuring and market redistribution.

While the very low fertility rates obtained from the various demographic surveys in the 1990s including the 2000 census are considered to be beyond belief,the very high sex ratios at birth(SRB)reported from the same surveys are widely accepted.The major objective of this article is to re-estimate China’s SRBs in the 1990s using the educational data by examining the sex differences in birth under-reporting in the 2000 census.Results show that the estimated SRBs were not as high as those reported in the census.The actual SRBs and sex ratios at younger age groups are estimated to be lower than those reported in the census by 5-9 percentage points.Under-reporting of female births is estimated to account for at least 50% of the excessive amount of the SRBs in the 1990s.Socio-economic differentials in the SRB are also examined in this article using the micro data of the 2000 census.

Using data from the one per thousand floating population survey in Beijing conducted in 2006, this paper examines structure, distribution, economic status and living arrangement of the floating population in Beijing. Structural changes of the floating population are taking place, with increasing familization of migration. Economic advantages are the major pulling factor in Beijing. Duration of stay in Beijing is quite long for most of the migrants, and many are the de facto Beijingnese. Being informal is characteristic of the ways in which the migrants move to and are being employed in Beijing. The vast majority of the migrant workers are engaged in non-agricultural activities; however, their upward mobility in the city is rare. The paper also discusses difficulties and problems that the migrants face in employment, social security and living conditions.

It has been a mystery how high Chinese fertility is in the 1990s.Using education statistics from Ministry of Health,which are independent of statistics from population-related departments,this paper assesses levels and patterns of underreporting in the 2000 census,thus estimating China’s fertility in the 1990s.Upon adjustment according to the education statistics,age-sex structure of population aged 0-9 of the 2000 census is reconstructed,which is then converted into annual number of births in 1991-2000,and fertility rates in the 1990s are reproduced.Estimates show that China reached replacement fertility in 1991,and had below-replacement fertility after that.China’s total fertility rate in the late 1990s stood at 1.7-1.8.