This study utilizes the longitudinal survey data to investigate the age group differences in the impact of changes in family structure on the mortality risk of rural older adults. The results show that ‘always being in a linear family’ significantly reduced the mortality risk of older adults. ‘Changing from a linear family to a one-person family or a conjugal nuclear family’ resultes in a decline of the mortality risk of the older adults under age 75 while lead to an increase after controlling the intergenerational support and health condition. It also increases the mortality risk of the older adults above age 75. ‘Changing from a one-person family or a conjugal nuclear family to a linear family’ significantly reduces the mortality risk of the older adults above age 75. The results reveal that Chinese society is in a period of transition and coexistence of traditional and relatively modern family structures. Changes in family structure based on respect and care for life that meet the multi-dimensional care needs of the older adults benefit the health and life expectancy of older adults. Supporting the health development of younger older people under the changes of family structure will also lead to better health conditions when they grow much older in the future, thus further promote the realization of a healthy aging society in China.

Drawing upon data from “Well-being of Elderly People in Anhui Province Survey” from 2001 to 2015，this paper explores the dynamic relationship between household composition change and elderly people’s subjective well being (self-rated health and life satisfaction).The results show that the influence of household composition change on the subjective well-being of the elderly depends on their age.For the younger-old age period of the elderly，the presence of grandchildren in household composition change has a positive impact on the subjective well-being of the elderly，whereas the household composition change in which elderly live alone or only live with their children，the subjective well-being of the elderly improves more slowly.For the oldest-old age period of the elderly，the five kinds of household composition change significantly deteriorates the development level of the subjective well-being of the elderly.The life satisfaction of the elderly shows a non-linear development with age.During the whole life-cycle of the elderly，the subjective concept，self-efficacy，and the family roles of elderly people differentiate the influence of household composition change on older people's subjective well-being，and the household composition change has selection effects on the older people’s health.

 Labor supply is an important source of economic growth．In this paper，we use the factorization method to quantify the contribution of labour supply in China's economic growth by decomposing the labor supply factor into the population size，the proportion of working-age population，and the labor participation rate factors．We put them all into the classic Cobb-Douglas production function．Based on the theoretical model derivation，this paper analyzes the time series data from 1978 to 2015．The results show that labor supply has a significant contribution to China's economic growth in a long term．Its impact and contribution are less significant than the fixed assets，but much greater than the human cap- ital．The main contribution of China's economic growth comes from the input of material capital rather than the labor supply．All of the three variables representing the scale of labor supply have significant effects on economic growth in the same direction，but the magnitude of the effects varies．The order of the contribution and elasticity of the three factors to the total economic output are the total population，the proportion of the working-age population，and the labor participation rate．Finally， in recent years the decrease of the proportion of working-age population does suppress China's economic growth，but this negative impact is to some extent offset by the increase in the size of the total population．

The optimum population under the constraint of resources and environment，by which both the con- straints of resources and the environment are met and a certain standard of living and development goals are achieved，is an important basis for China’ s future population policy considerations．Based on the concept of optimum population and the analysis of its internal mechanism under the constraint of resources and environment，12 indexes are selected from the fields of natural resources，environmental and socioeconomic development．Using the possibility- satisfiability model，we separately estimate the optimum scale of China’ s population under a single factor and different combinations of indexes in both 2030 and 2050 as the target point time．The results show that the lowest value of China’ s optimum population under the constraints of major resources and environment is around 1157-1322 million in 2030 and 1465-1626 million in 2050，while the desired optimum population of China would be 986-1311 million in 2030 and 1188-1389 million in 2050． Water resource is always the most important factor in restricting China’ s population growth in the future．The relationship between population，resources and environment would be more strained by 2030，and then would tend to improve after 2050．

There is much controversy over definition and measurement of family well-being，challenging the government’s effort to construct happy families．Based on the sampling survey data in Beijing in 2014，this paper explores the significant differences in family well-being among various family types and the possible determinants of family well-being．Taking families as the analysis unit，the paper constructs the standardized scores of family well-being and summarizes relevant variables into 7 factors as control variables．The results show that all sample families are moderately happy，and compared to the intact families，those that are sectional have statistically significantly lower scores of family well-being．However，MLRmodel denies the effect of family type on family well-being and admits the roles of member relationship factor，security level factor and spousal relationship factor．