Abstract: The Bacteria composition of Tan lamb and predominant flora changes with storage time extension were discussed by sequencing the microbial community of Tan lamb during the storage with Illuminu sequencing technology.The results indicated that the microbial flora showed diversity during the storage of Tan lamb. The microorganisms in the Tan lamb were constituted of 11 phylum of bacteria,23 classes and 35 genuses during its different storage periods,but it has showed different richness of bacteria in the different periods.With the extension of storage time,in the 8th day,the main bacterial populations on the surface of the cold fresh Tan lamb were:71.59% Proteobacteria; 23.15% Firmicutes.The proteobacteria showed a decreasing trend with increase of storage time,but the Firmicutes changed in contrary. As the storage time increased,the Pseudomonas in Proteobacteria accounting for the most of the bacteria,which was the Specific Spoilage Organisms that caused clod fresh Tan lamb's corruption.