This article systemically reviews the “Second Demographic Dividend” theories and dissects the inner functional mechanisms. Base on the perspective of dual capital deepening, we reexamine and predict the “Second Demographic Dividend”. We use the theoretical model and numerical method to do the simulation analysis. The study finds that the inner driving mechanism of the “Second Demographic Dividend” roots in the sustaining action of the “Demographic Prospective Dividend” and the “Demographic Quality Dividend”. The moderate ageing and low birth rate of our country can help form the “Demographic Prospective Dividend” and lengthen the “QuantityQuality substitution”. The “Demographic Prospective Dividend” and the “Demographic Quality Dividend” can strongly promote economic growth by the dual capital deepening. The numerical modeling suggests that the excessive high ageing rate and excessive low birth rate can weaken this effect farther. So we should put the appropriate population and economic policies into effect to ensure the achievement of the “Second Demographic Dividend” by our country.

 In order to understand the life satisfaction status and the correlation between social support and life satisfaction of young migrants，and to provide theoretical basis for formulating targeted management and service measures，a questionnaire survey was conducted in March to May 2015．A total of 2998 qualified young migrants were selected and analyzed．The results show that young migrants in different regions have significantly different life satisfaction，with the life satisfaction in Beijing being the highest．Social support has significant positive influence on life satisfaction．Migration type，education， economic situation and health status have significant impact on life satisfaction of young migrants．Thus government departments should collaborate and combine with the specific situation of different regions to provide effective social support and improve life satisfaction of young migrants and social stability．