The antimicrobial action of Pyrola calliantha extracts (PCB) against a series of microbe was studied. The results showed that the antimicrobial effect of PCB varies with the pathogenetic microbes. The minimum antimicrobial dosages of PCB for different microbes were as follows: 5% for Staphylococcus aureus; 20% for Pseudomonas aeruginosa, 10% for Escherichia coli, 10% for Rhizopus, 20% for Penicillium. The more the concentration of PCB, the higher the antimicrobial activity was. It was also proved that PCB had moderate thermo-stability and the addition of sugar or salt can improve the antimicrobial activity. Besides, the longer the action time of PCB with the same concentration will bring higher inhibition rate.