Abstract: Chinese sourdough is a traditional raw material in fermented pasta, most of which is produced by using wheat flour, rice, corn flour, bran and the other cereal grains as the base. In brief, water is mixed with the base in a certain proportion, and sourdough is formed after repeated natural fermentation and air drying. It is widely used at home and abroad. The Chinese sourdough fermentation technology is still used in northern China to effectively improve the flavor of Chinese steamed bread, which is widely accepted by consumers. Chinese sourdough is a complex biochemical system, where key flavor substances participating in the formation of steamed bread cannot be separated during microbial metabolism. At present, there are extensive researches on the flavor analysis of sourdough, steamed bread and the microbial diversity of Chinese sourdough. It is of great importance to construct a metabolic pathway between the microorganism and volatile substances. In this study, two kinds of dough added with Chinese sourdough or not were compared, the changes in the microbial structure of the two during the fermentation process were studied through traditional culture combined with high-throughput sequencing. Besides, the correlation analysis was performed in conjunction with the changes in flavor during the fermentation process. Chinese sourdough from Xinxiang for making fermented dough was collected to shorten the fermenting time and improve the fermented flavor of the dough. Through the analysis of microbial diversity, the study showed that as the fermentation progressed, Rhodotorula glutinosa appeared in the sourdough in the traditional culture, and the total number of colonies is higher than that of Angel dough. The high-throughput sequencing results showed that among the top ten abundant bacteria genera, Lactobacillus and Bacteroides appeared in the Chinese sourdough, and the number is higher than that of Angel dough. The detection results of flavor substances showed that a total of 126 volatile components were detected, among which esters, alcohols, aldehydes and other flavor components ranked the top in the substances list, and the esters percentage increased with the time elongated. According to the correlation analysis of microorganisms and flavor components, Mucilaginosa isolate had a close correlation with aldehydes and ketone flavor substances. By comparing and analyzing the changes of microbial diversity and flavor substances during the fermentation process of steamed bread, this study provided a theoretical reference for further study of the flora information to improve the characteristic flavor and quality of steamed bread.