Abstract: In this study,the bacterial diversity of mutton during processing was analyzed by traditional culture and high-throughput sequencing. The results of traditional culture showed that bacterial counts on the surface of carcass were in range of 10³~10⁴ CFU/cm² during the first processing of mutton,and they increased to 10⁵~10⁶ CFU/cm² in the subsequent segmentation process,indicating that the mutton may be contaminated. Forty-three strains were isolated from traditional cultures,and were identified as Aeromonas,Enterobacter,Proteus,Staphylococcus and Escherichia coli by 16S rDNA sequencing. The Enterobacter stains had the strongest ability of biofilm formation by crystal violet staining results. High-throughput sequencing revealed that the spoilage bacteria on the surface of the corpus callosum and carcass were mainly Moraxellaceae,Aeromonadaceae,Acinetobacter Flavobacteriaceae,Shewanellaceae,Pseudomonadaceae,Listeriaceae,Staphylococcaceae and Enterobacteriaceae. This study found that the carcass during processing was contaminated with many different spoilage bacteria,which was useful for the further study mutton storage.