Abstract: This study investigated the antimicrobial activity of the maillard reaction products which were obtained from enzymolysis polypeptide of pelagicus meat ( PXMRPs) on four selected spoilage bacteria frequently found in food including Staphylococcus aureus, Waxy bacillus, Bacillus subtilis and E.coli, and the preparation of PXMRPs process was optimized. The results revealed that the PXMRPs had obvious germ inhibiting effect on the four bacterias. Xylose as the reducing sugar, substrate ratios of xylose and enzymolysis polypeptide of pelagicus meat, temperatures and the reaction time were independent variable in the maillard reaction, the diameter of inhibition zone were measured during single factor test and the orthogonal experiment which was to find the optimal parameter of processing in order to strengthen the antibacterial efficiency of PXMRPs.The optimal processing conditions were that the ratio of enzymolysis polypeptide of Portunus pelagicus and xylose was 2∶ 1, the temperature was 120 ℃, the reaction time was 120 min. And the MIC ( minimum inhibitory concentration) values of Waxy bacillus and Staphylococcus aureus were both 15 mg/m L, the MIC values of Bacillus subtilis and E.coli was 20 mg/m L and30 mg/m L, respectively. Therefore, enzymolysis polypeptide of Portunus pelagicus meat showed strong antimicrobial activity because of the modification of maillard reaction, PXMRPs can be used as an antimicrobial in food industry.