Abstract: The aim of the study was to explore the synergistic antimicrobial effect of punicalagin and chlorogenic acid against Staphyloccocus aureus and to elucidate its mechanism. The checkerboard microtiter tests were used. The growth curve, intracellular pH (pH_in) and membrane potential were measured to illustrate the antibacterial mechanism. Morphological changes induced by punicalagin and chlorogenic acid were examined by electron microscopy. The results showed that compared with 1/4 MIC punicalagin or 1/16 MIC chlorogenic acid, the combination of punicalagin and chlorogenic acid displayed strong synergistic antibacterial effect against Staphyloccocus aureus, resulting a notable reduction in (pH_in-pH_out), cell membrane depolarization andmembrane disruption. There was a noteworthy difference in membrane potential or (pH_in-pH_out) between the combined group and the control group. In conclusion, there was a notable synergistic antimicrobial effect of punicalagin and chlorogenic acid against Staphyloccocus aureus, which can be achieved by destroying the cell membrane integrity.