Using China Family Panel Studies (CFPS) of 2010，2012 and 2014，this paper explores the impact of retirement on Chinese elderly＇s physical and mental health based on the mandated retirement age policy within a framework of regression discontinuity (R D)． The mechanism of the impact of retirement on health is further tested． The results show that the impact of retirement on the health of males is not significant，while retirement has a significant positive influence on females ＇ self － rated health and mental health，the mechanism of which is that retirement significantly increases female physical exercise per week． Although retirement increases male physical exercise per week in a similar manner，it also raises the probability of overweight for males，which is likely to offset the effect of exercise to a certain extent．Chinese government is considering implementing policies for gradually postponing the retirement age of employees． The results of this paper indicate that postponing retirement should not be made at the expense of elderly＇s health，and China needs to push forward the“healthy aging”strategy．

Using the Solow growth theory and a modified Cobb-Douglas production function which contains human capital,this paper analyzes the impact of population aging and population growth on economic growth.Theoretical analysis shows that both population aging and population growth have negative influence on economic growth.Empirical models on the basis of theoretical analysis are constructed and China′s provincial panel data from 1990-2008 for empirical test are collected.Model results correspond to the results of theoretical analysis.The research also shows that:(1) initial GDP per capita has negative effect on economic growth,indicating conditional convergence in China′s regional economic growth;(2) human capital investment,saving rate and labor force participation rate all have positive influence on economic growth.