Abstract: The antioxidant ability, bacteriostasis, emulsibility and stability of Pleurotus eryngii polypeptide using Pleurotus eryngii as raw material was studied in this experiment.Identified the DPPH·, O-2·and other free radicals, bacteria growth and lipid peroxidation were affected by the polypeptides, then researched the emulsifying properties.The results showed that Pleurotus eryngii polypeptide had strong ability in scavenging DPPH·, O-2·and a certain inhibition of lipid peroxidation.With the concentration increasing, scavenging activity and inhibition ratio also increased which were 85.94%, 80.66%, 45.57% respectively when the polypeptide concentration was 2%.The studies showed that Pleurotus eryngii polypeptides had good emulsification and emulsion stability and a strong inhibitory effect on Staphylococcus aureus, Salmonella, E.coli. The inhibition rates were 57.7%, 55.5%, 87.1%respectively.The experiment results provide a theoretical basis for the development of Pleurotus eryngii proteins and poly-peptide.