The bulging of soy sauce bags always happened in spring and summer,which is mostly caused by microorganisms. In this paper,high glucose medium,nutrient agar,MRS medium,and potato sucrose medium were used to isolate microorganisms from the explosion soy sauce samples produced from Shaoxing. Only 7 kinds of bacterial strains named as k1,k2,k3,k4,k5,k6,k7were purified from nutrient agar. The results form gas production experiments confirmed that only k2strain can produce gas in soy sauce. Based on the systematic analysis of its colony morphology and characteristics,physiological and biochemical characteristics according to Bergey's Manual of Determinate Bactertology,strains k2was identified as Bacillus megaterium.