Abstract:In order to reveal the differences in bacterial communities and physicochemical indices of three types of high-temperature Daqu（yellow Daqu，white Daqu，and black Daqu），and initially investigate the causes of the functional differences between the different types in the fermentation process，we investigated the differences in bacterial communities between different types of high-temperature Daqu and the effects of endogenous and exogenous factors on the dominant microorganisms by means of amplicon sequencing，strain culturing，correlation network analysis and redundancy analysis（RDA）.The results showed that Kroppenstedtia，Saccharopolyspora，and Arthrobacter were the dominant bacteria in the fermentation process of yellow Daqu；Saccharopolyspora，Thermoactinomyces，and norank_Bacteria were the dominant bacteria in the fermentation process of black Daqu；while Bacillus，Thermoactinomyces，Saccharopolyspora，and Weissella were the dominant bacteria in the fermentation process of white Daqu.The RDA results showed that among the above microorganisms，the dominant bacteria genera that is closely related to yellow Daqu was Kroppenstedtia had a strong negative correlation with moisture content；Bacillus was positively correlated with the amount of saccharification，which might be the reason for the higher saccharification power of white Daqu；and Thermoactinomyces，which was the dominant bacteria in the late stage of black Daqu fermentation，had an positive correlation with acidity and negative correlation with moisture.The above findings preliminarily reveal the driving factors of bacterial structure succession in Daqu，and provided an important theoretical basis for improving the quality of high-temperature Daqu.