Abstract: Abstract：The formation of Nongxiangxing Baijiu flavor is inseparable from the microbial metabolism which influences the physicochemical environment of the fermented grains. In order to clarify the succession law and potential function of microbial in the fermented grains of Nongxiangxing Baijiu. High-throughput sequencing was borrowed to reveal the succession of microbial community structure , and the relationship between microbial community structure and physicalchemical indicators was analyzed in different fermentation stages. PICRUSt analyse was used to predict the potential function of bacterial community in the fermented grains. The results showed that Firmicutes, Proteobacteria, Actinobacteriota, Ascomycota, and Basidiomycota were the dominant phylums in the fermented grains. The dominant microorganisms were Lactobacillus、Bacillus、Staphylococcus、Thermoactinomyces、Kazachstania、Wickerhamomyces、Penicillium、Candida、Aspergillus、Meyerozyma、Debaryomyces，Lactobacillus、Kazachstania and Wickerhamomyces being absolutely dominant. The correlation analysis between physicochemical indicators and microbial diversity showed that reducing sugar and starch have a significant positive correlation with 8 bacteria. Acidity and moisture have a significant negative correlation with 10 bacteria. Some fungi are significantly correlated with physicalchemical indicators.PICRUSt analysis showed that the relative abundance of functional enzymes at different fermentation stage was significantly different, and the dominant microbial in the fermented grains participate in glycolysis, acid metabolism and ethanol synthesis to form a complete metabolic chain, indicating that the succession of the microbial community of the fermented grains is the main reason for the differences in metabolism at different fermentation nodes. This study analyzes the succession law of microbial community structure in the fermented grains and their metabolism in the fermentation process, which provides a theoretical basis for the study of the metabolic mechanism of baijiu brewing microorganisms.

Key words: Key words：Nongxiangxing baijiu, fermented grains, microbial community, correlation analysis