Using data from censuses and statistical yearbooks between 2000 and 2020 and World Population Prospects 2022, this study constructs a comprehensive evaluation model for labor force quality to estimate the nominal labor supply and effective labor supply equivalent in China and analyze the feasibility and realization path of population quality complementing population quantity. The results show that China's nominal labor supply will drop from 744.7 million in 2020 to 565.9 million in 2050. Although the effective labor supply equivalent is higher than the nominal labor supply, it is constrained by the decline of the labor force. The effective labor supply equivalent will peak at 752.9 million in 2028 and then drop to 643.1 million in 2050. By improving the relative labor quality through educational reform and health interventions, the year of the peak can be postponed until 2032, and it can remain over 714 million before 2050, achieving the population quality complementing quantity in the short term. In the long term, fully leveraging the compensatory effect of population quality cannot be achieved without a certain population size. It is necessary to strengthen the policy system further to support fertility.

Based on the period age-specific fertility rate,this paper has proposed an estimation method of the cohort age-specific fertility rate and uses data of the birth cohort of 1950-1981 to explain its feasibility and reliability.This method can be applied to analyze the pattern of parity progression and related issues,particularly for the adjustment of Chinese family planning policy.Using this method,this paper has estimated the quantity and structure of women with one child,and women who are allowed to have two children by the current family planning policy but have had only one child.This would have implications for family planning policy research.

China and India are the largest population countries in the world. The sex ratio at birth (SRB) of both of them have become higher than normal scale and rising since the early of 1980s. Currently,China’s SRB is around 120 per 100 females,and India is 113. Estimate of basing on the census data of India (2001) and China (2000),the size of missing girls between 0 to 19 years old in India and China is 11.9457 millions and 16.1242 millions,and their rate of missing girls is 6.12% and 6.82% respectively. This number and rate of China decreased with age,mainly to the prenatal female missing because of higher SRB,sex selective abortion and female missing report or under report. But the India’s indicators increased with age,mainly to postnatal female disappearance because of the lower sex ratio of age specific mortality rate and male superior living condition than female at young age.