Research on the change of fertility level and the development of China’s population structure under the comprehensive two-child policy

Through the construction of population actuarial model and parameter design, this paper studies the dynamic trend of China’s population structure development from 2018 to 2050 under the comprehensive two-child policy The study found that for every 0.1 increase in the total fertility rate under the comprehensive two child policy, the average annual growth rate of the total population will increase by 0.06%-0.07%, the average annual growth rate of population aging will decrease by 0.15%-0.19%, the average annual growth rate of the total dependency ratio will increase by 0.080%- 0.036%, the average annual growth rate of the elderly dependency ratio will decrease by 0.17%-0.23%, and the average annual growth rate of the child dependency ratio will increase by 0.09%-0.18%, The annual average decline rate of gender ratio between men and women will be reduced by 0.001% This shows that the increase of the total fertility rate under the comprehensive two child policy can significantly alleviate the decline rate of the total population, significantly improve the rising rate of China’s population aging, significantly reduce the rising rate of the elderly dependency ratio, but also significantly increase the rising rate of the total dependency ratio and the child dependency ratio, and significantly inhibit the decline rate of the gender ratio of men and women At the same time, even if every couple has two children from 2018 to 2050, China’s population change situation is still not optimistic Finally, based on the empirical results, policy suggestions are put forward.