In order to explore the spoilage ability and gene characteristics of Brochothrix thermosphacta in beef， 29 strains were obtained by purification， morphological observation and PCR identification from chilled beef. The spoilage potential of these isolates was evaluated by the production of total volatile basic nitrogen(TVB-N) and acetoin index in beef juice at 4 ℃. The whole genome sequences of strong and weak spoilers were compared. The results showed that the TVB-N values increased slowly， and only two strains exceeded 11.5 mg N/100 g on the 9th day. In contrast， these isolates strongly produced acetoin， and their producing abilities differed. The acetoin contents of strain BT27 and BT25 were 139.3 μg/mL and 59.5 μg/mL， respectively. The whole genome sequencing of BT27 and BT25 showed a large number of genes involved in carbohydrate metabolism， the largest number of genes was encoding glycoside hydrolase， followed by glycosyltransferase genes. Comparative genomics showed that the number of genes encoding carbohydrate metabolism and corresponding enzymes of strong spoiler BT27 was more than that of weak spoiler BT25， while the number of genes encoding amino acid metabolism was similar between them. This study indicated that the spoilage ability of B. thermosphacta was correlated to the number of genes encoding carbohydrate metabolism， which provided the genetic point of view for elucidating the spoilage mechanism of meat microbiology.