Abstract:This article first from the steamed bun JiaoZi microbial screening，initial separation and purification，pure yeast and lactic acid bacteria were screened.Second set of yeast and wheat flour in different proportion and different mixed fermentation temperature gradient，with the odourof the dough，the size of the porosity and distribution measurement standard，screening of fermenting power good strains.Then mix yeast species and strains of lactic acid bacteria fermentation，steamed buns，with the perfume of steamed bread，hardness testing，to choose the optimal matching，improveing the quality of bread.