Abstract: Objective:To investigate the antimicrobial actions about the water extract and the alcohol extract of Prinsepia utilis tea. Methods:The tube 2-fold dilution method and Kirby-Baueer Disc Diffusionto were used to test the inhibitory of the two extract for S.aureus and E. coli. To compare the two extract's antimicrobial effect against the E. coli and S. aureus, the antibacterial circle diameter, minimum inhibitory concentration (MIC) and minimal bactericidal concentration (MBC) were measured. The influence of pH and temperature on Prinsepia utilis tea bacteriostatic action were further studied. Results:The water extract of P. utilis tea had antimicrobial effect on both S. aureus and E. coli, specifically, its antimicrobial effect was more apparently on the E. coli than the S. aureus, while the ethanol extract of P. utilis tea only had bacteriostatic effect on E. coli. The optimum bacteriostatic pH for water extract was 5 to 6. Conclusion:The water extract of Prinsepia utilis tea had the strongest antimicrobial actions on E. coli. Compared with the alcohol extract, the water extract had relatively stronger antibacterial effect.