Objective To study the inhibitory effects of natural antibacterial agent on Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Candida albicans and Aspergillus niger. Methods The diameter of inhibition zoon and the minimum inhibitory concentration (MIC) of natural antibacterial agent against 5 pathogenic microorganisms and MICs of 10 strains of Staphylococcus aureus were determined by cup and dish method,microporous plate method. Result The diameter of inhibition zoon of 1% natural antibacterial agent against S.aureus, E.coli, P.aeruginosa, C.albicans and A.niger were 14.47mm, 10.67mm, 9.13mm, 28.13mm and 10.53mm, respectively. The MICs of natural antibacterial agents against S.aureus, E.coli, P.aeruginosa, C.albicans and A.nigerwere 0.08%, 0.16%, 0.63%, 0.08% and 0.16%, respectively. The MICs of Sensiva SC50 against these five microorganisms were 0.16%, 0.16%, 0.31%, 0.16% and 0.13%, respectively. The MICs of 10 strains of S. aureus were 0.08%、0.06%、0.05%、0.09%、0.06%、0.07%、0.10%、0.06%、0.09%、0.07%, respectively. Conclusion The natural antibacterial agent had a certain inhibitory effect on the five microorganisms, the inhibitory effects on S. aureus and C.albicans were better than the positive control, the inhibitory effects on E.coli, and A.niger were similar to the positive control, and the effect on P.aeruginosa was slightly worse than the positive control. And all the 10 stains of S. aureus showed good inhibitory effect.