Abstract: The study starts with the temporal and spatial volatility rule of China's birth rate in recent years, adopting ridge regression model to divide the stages of birth rate's fluctuation according to the discrepancies of correlation between birth rate and related independent variables, then further the analysis of macro and micro factors affecting the volatility of the birth rate and reveal the temporal volatility rule of China's birth rate. In the meantime, the research about differences of influencing factors and degree on birth rate among 29 regions is carried out by constructing a panel for 29 regions between 1990 and 2012, based on which the appropriate suggestions will be proposed to further the reform on fertility policies and supporting mechanisms.