Abstract: The bacteriostasis and bacteriostasis mechanism of fermented beef flavorings(FBF)were studied. In the experiment,WBL-45(Staphylococcus xylose+Staphylococcus bovis+Lactobacillus sake),VHI-41(Staphylococcus xylose+Staphylococcus pentosus+Lactobacillus plantarum),Lactobacillus sake(LS)were used as starters to prepare FBF after high-pressure extraction,enzymolysis,fermentation and Maillard reaction of bovine bone and meat powder,Escherichia coli,Salmonella paratyphoid B and Staphylococcus aureus were the target bacteria. The inhibition concentration 50(IC₅₀)of FBF on three pathogenic bacteria in different treatment groups was studied by optical density method. The growth curve of target bacteria after FBF treatment was studied,the bacteriostatic effect of three groups of FBF was evaluated. The morphology of bacteria was observed by scanning electron microscope,and the relative conductivity was measured to understand the permeability of cell membrane. The bacteriostatic mechanism of FBF was expounded. The results showed that the IC₅₀ of E. coli,Salmonella paratyphi B and Staphylococcus aureus in WBL-45 group were 3.75,7.5,3.75 mL/100 mL,respectively. The IC₅₀ of FBF in VHI-41 group and LS group were 3.75,3.75,1.88 mL/100 mL respectively. The normal growth and proliferation of the three indicator bacteria were inhibited,the delayed period was prolonged,the maximum specific growth rate and the amount of bacteria in the stable period were reduced,the normal morphology of the bacteria was destroyed by FBF,and the surface of the bacteria was folded and holes,normal transmission and transport of nutrients in the bacteria were affected,so that the growth of the indicator bacteria was inhibited.