Abstract:In order to clarify the structure of microbial community in pit mud of one Luzhou-flavor liquor of Yujiu enterprise，Illumina Miseq high-throughput sequencing technology was used to analyze the diversity and composition of prokaryotic microbial communities in the walls and bottom mud for 4 years and 40 years.The results showed that there was no significant difference（P>0.05）between observed operational taxonomic units（OTU），Chao1 and ACE of pit mud，and the Shannon and Simpson of 40 years pit bottom mud had significant significance（P<0.05）.The dominant phylum of the pit mud was Firmicutes，Proteobacteria，Bacteroidetes，Euryarchaeota and Actinobacteria.There were 12 dominant genus.The dominant genus was Lactobacillus，Caproiciproducens，Acinetobacter，Petrimonas，etc，belonging to 4 phylum，and mainly concentrated Firmicutes.Firmicutes had an absolute advantage in the pit bottom mud for 40 years，Bacteroidetes and Eur－yarchaeota had higher contents in the pit bottom mud for 4 years and the pit wall mud for 40 years.Lactobacillus was the first dominant bacterial genera of wall and bottom pit mud for 40 years.While the first dominant bacteria of wall and bottom pit mud for 4 years were Acinetobacter and Caproiciproducens，respectively.Redundancy analysis（RDA）showed that the total acid（30.7%）and pH （15.7%）had the highest correlation with the dominant microbial community in the pit mud （P<0.05），indicating that total acid and pH were the dominant physicochemical factors affecting the distribution of dominant bacteria in different types pit mud.