OBJECTIVE： To study the antimicrobial activity of ampelopsin combined with 8 kinds of antibiotic against Pseudomonas aeruginosa （PA） in vitro. METHODS： Chessboard trace dilution method was used to determine minimum inhibitory concentration （MIC） of ampelopsin combined with ceftriaxone， cefoperazone/sulbactam， piperacillin/tazobactam， cefoperazone， ciprofloxacin， amikacin， piperacillin and cefepime to PA strain ATCC27853 and 7 isolated strains PA135， PA216， PA276， PA281， PA291， PA314 and PA319. Fractional inhibitory concentration index （FICI） was used to evaluate its effects of drug combination. Clinically isolated strain PA319 were taken as target strain and then divided into normal control group， ampelopsin alone group， antibiotics alone group and ampelopsin+antibiotic combination group. Using MIC of ampelopsin and antibiotics during drug combination as active concentration， the number of colonies cultured for 0， 4， 8， 12 and 24 h was counted， and the time-sterilization curve was drawn. RESULTS： For above 8 kinds of strains， MIC of ampelopsin alone was 128-256 mg/L； FICI of ampelopsin combined with ceftriaxone， cefoperazone/sulbactam， piperacillin/tazobactam， cefoperazone， ciprofloxacin， amikacin， piperacillin and cefepime to 8， 8， 7， 6， 4， 4， 6 and 6 strains were equal to or lower than 1， respectively. In time-antibacterial curve， compared with antibiotics alone， the number of colonies decreased by 2.65， 2.30， 0.42， 0.47， 0.53， 1.19， 1.74， 1.04 lgCFU/mL respectively after ampelopsin combined with ceftriaxone， cefperazone/sulbactam， piperacillin/tazobactam， cefoperazone， ciprofloxacin， amikacin， piperacillin and cefepime. CONCLUSIONS： Ampelopsin combined with ceftriaxone and cefoperazone/sulbactam show better antibacterial effect on PA.