Bacteriocin A32 extracted by acid precipitation was used on Escherichia coli and Staphylococcus aureus. The antibacterial activity and antibacterial mechanism of bacteriocin A32 were investigated by Oxford Cup method， spectrophotometry， scanning electron microscope， electrical conductivity and SDS-PAGE method. The results showed that bacteriocin A32 had antibacterial properties against E. coli and S. aureus， and the minimum inhibitory concentration was 1.25 mg/mL. It had effects on the production curve of the indicator bacteria， cell morphology， cell membrane permeability， cell membrane permeability， cell membrane integrity， cell wall， and protein synthesis. And with the increase of the concentration of bacteriocin A32， the effect gradually increased. The results showed that the antibacterial properties of bacteriocin A32 were due to the damage to the permeability and integrity of the wall membrane of Gram-positive and Gram-negative bacteria， resulting in leakage of the contents， which in turn affected the metabolism and growth of the bacteria. The above research can lay a theoretical foundation for the development and application of bacteriocin A32 as green biological preservative.