Abstract: The synergistic effect on the antibacterial activity of the natural antibacterial ingredient(ovalbumin)was investigated by adding a low concentration of biopreservative lactic acid as a synergist. The effects of lactic acid concentration,treatment temperature and time on the ability of ovalbumin to inhibit pathogenic bacteria(Escherichia coli O157:H7,Staphylococcus aureus)and spoilage bacteria(Paenibacillus lautus,Proteus terrae)were investigated by single factor experiments,and the optimal lactic acid treatment conditions were obtained. Under these conditions,the increase rate of the antimicrobial activity of ovalbumin and the bacteriostatic kinetic curve were determined. The results showed that the antibacterial activity of ovalbumin against Paenibacillus lautus and Staphylococcus aureus were respectively increased by 7.802% and 26.904% after treatment with 0.05% lactic acid for 40,60 min at 4 ℃. For Proteus terrae and Escherichia coli O157:H7,after respectively treatment with 0.15% and 0.2% lactic acid for 40 min at 25 ℃,the antibacterial activity of ovalbumin were increased by 53.770% and 131.321%,respectively. The antimicrobial kinetic curve showed that lactic acid extremely significantly increased(p<0.01)the antibacterial activity of ovalbumin,decreased the applied concentration and prolonged the bacteriostatic time of ovalbumin.