By analyzing the internal relationship between the two demographic dividends and high savings, using OLG model with intergenerational factors to make qualitative judgments, this paper makes an empirical analysis on the relationship among life expectancy, dependency ratio and household savings rate based on fixed effect model, random effect model and panel threshold model. The result finds that the increase of life expectancy can significantly increase the household saving rate. The increase in child dependency ratio can significantly decrease the household savings rate, and the increase in elderly dependency ratio can promote the increase in household savings rate. Within different thresholds, the coefficients of child dependency ratio and elderly dependency ratio have changed. Therefore, it is concluded that the aging and low birth rates have heterogeneity effect on the saving rate in regions with different economic levels in China.