Illumina MiSeq high throughput sequencing technology was used to study the bacterial community，abundance and dynamic change of the traditional light-flavor baijiu during fermentation processes. A total of 319 872 and 269 087 effective sequences and 39 567 and 22 717 OTUs were obtained， which were classified into 15 phyla （Firmicutes，Proteobacteria， Bacterioidetes， Planctomycetes， Actinobacteria， Chloroflexi， Verrucomicrobia， Acidobacteria， Gemmatimonadetes， Chlamydiae， Nitrospirae， Euryarchaeota， Cyanobacteria， Deinococcus-Thermus， Fusobacteria）. The results showed that species and quantity of bacteria was changed with environmental change and fermented time. It was largely different for bacterial community and abundance of Dacha and Ercha’s sample. These high-throughput bacterial genome sequencing revealed generation of all the bacteria. Pediococcus， Lactobacillus， Staphylococcus were predominated microorganisms in all fermentation processes， and they play an important role to flavor formation of the traditional light-flavor baijiu.