OBJECTIVE To investigate the antibacterial activities of flavaspidic acid BB against the main pathogens of skin and soft tissue infections such as methicillin -resistant Staphylococcus aureus （MRSA）and methicillin -sensitive Staphylococcus aureus （MSSA） in vitro and in vivo . METHODS Microdilution method was used to determine the minimum inhibitory concentration（MIC）and minimum bactericidal concentration （MBC）of flavaspidic acid BB on 10 strains of MRSA and 13 strains of MSSA ；time-kill curves of MRSA 11 and MSSA 23 strains were drawn by plate method ；the checkerboard dilution method was used to determine the combined antibacterial effect of flavaspidic acid BB and mupirocin ；the skin abscess model of mice was established to evaluate the antibacterial effects of 0.5%，1%，2% flavaspidic acid BB cream on MRSA 11 or MSSA 23 strains in vivo；scanning electron microscopy was used to observe the effects of flavaspidic acid BB on the morphology of MRSA 11 or MSSA23 strains. The contents of nucleic acid leakage and extracellular protein were also determined . RESULTS MIC and MBC ranges of flavaspidic acid BB against 10 strains of MRSA were 6.30-80.00 μg/mL and 40.00-640.00 μg/mL；MIC and MBC ranges of 13 strains of MSSA were 40.00-80.00 μg/mL and 63.50-126.99 μg/mL，respectively. The bactericidal rate of MRSA 11 and MSSA23 strains were 99.9% after interfered with plavaspidic acid BB for 36 h. The combination of flavaspidic acid BB and mupirocin showed an additive effect on MRSA strain and an additive or synergistic effect on MSSA strain . The 0.5%，1% and 2% flavaspidic acid BB cream could reduce the volume of abscess and the bacterial load of skin abscess model mice to some extent （P＜0.05），and improved the pathological changes of skin inflammation in skin abscess site of mice . Flavaspidic acid BB could make MRSA 11 and MSSA 23 cells shrinkage and rupture ，and significantly increase the contents of nucleic acid leakage and extracellular protein （P＜0.01）. CONCLUSIONS Flavaspidicacid BB shows good antibacterial effect on MRSA and MSSAE-mail：tchp66@163.com in vitro and in vivo ，the mechanism of which may be related to the change of membrane permeability .