In order to explore the change rule of microorganism and physical and chemical factors during the fermentation of rice flavor Baijiu， this experiment measured the physical and chemical indexes and microbial community changes on the 0， 1， 2， 3， 4， 5， 6， 7， 8， 15， 22， 29， 36， 43， 50， 64 and 94 days during the fermentation process. The results showed that during the fermentation stage， pH showed a trend of decreasing first， then increasing and then decreasing， and at the end of fermentation pH was about 4.1， while total acid showed a gradual increase trend. The starch content is rapidly hydrolyzed and consumed in the early stage of fermentation， and tends to be flat in the later stage of fermentation. However， the reducing sugar content shows an increasing trend within 0-2 days of fermentation， reaching a maximum value of about 180.14 g/L on the second day. Within 2-15 days， it is utilized by microorganisms and its content rapidly decreases. In the early stage of fermentation (0-3 d)， no alcohol content was generated， at 22 days of fermentation， the alcohol content reached its maximum value of 9.5°，however， in the later stage of fermentation， the alcohol content decreased. The total phenol content showed an increasing trend with the increase of fermentation time， and the final content was 375.63 mg GAE/L at the end of fermentation. In the fermentation process， Proteobacteria and Firmicutes were the main dominant bacteria， and the main dominant bacteria were Enterobacter， Pantoea， Pediococcus and Lactococcus. The results of the principal coordinate analysis showed that all samples were divided into 6 clusters on the PCoA plot， Redundancy analysis (RDA) showed that Lactococcus， Pseudomonas and Pediococcus were positively correlated with total acid composition， Pantoea， Cronobacter， Enterococcus and Klebsiella were negatively correlated with total acid composition. However， Pantoea， Cronobacter， Enterococcus and Klebsiella were positively correlated with pH， starch (St) and reducing sugars (Rs)， and total acids had the greatest impact on the dominant bacteria， pH， starch (St) and reducing sugars (Rs) had similar effects on the dominant bacteria.