Based on the comprehensive influence of consumption habits，income，interest rates，uncertainty，and liquidity constraints，and considering the heterogeneity of precautionary saving motives，we structure a dynamic panel model to explain the strength and reasons of precautionary saving motives of urban inhabitants in China during 1999-2011 by using the panel data of 31 provinces．The results show that: ①Consumption habits，income，the elderly dependency ratio，the ratio of male to female，real interest rates are important factors that influence the consumption of urban residents in China，but not important factors to promote precautionary saving motives; ②The strength of precautionary saving motives of urban residents is obviously improved when the heterogeneity of precautionary savings motives is considered．The uncertainties of the housing reform and the education reform are the major factors to the heterogeneity of urban inhabitants’precautionary savings motives．So，in order to improve the situations of high saving rates and low consumption，the key is to reduce the expected uncertainty of the consumption expenditure caused by the reforms of education and rising house prices．