Abstract: OBJECTIVE To evaluate the antibacterial activity of Lianhuaqingwen combined with meropenem against clinical isolates and drug-resistant strains in vitro. METHODS Solution of Lianhuaqingwen extract powder was prepared and diluted with 96-well plate microbroth method. The bacteria inhibition of Staphylococcus aureus, Escherichia coli and Pseudomonas aeruginosa was studied in vitro.The antibacterial concentration of Lianhuaqingwen and meropenem against carbapenems-resistant P aeruginosa and carbapenems-resistant Acinetobacter baumannii in vitro was determined by microchisboard dilution method, and the antibacterial index (FIC) was calculated and compared. RESULTS The minimum inhibitory concentration (MIC) of Lianhuaqingwen against S aureus, E coli and P aeruginosa was 2, 128 and 64 mg/ml, and the minimum bactericidal concentration (MBC) was 8, 128 and 128 mg/ml, respectively. The sensitivity of carbapenems-resistant A baumannii to Lianhuaqingwen and meropenem was increased with the combination of 16 mg/ml Lianhuaqingwen and 16 ug/ml meropenemy. CONCLUSION Lianhuaqingwen has antibacterial effect on common pathogenic bacteria. Lianhuaqingwen combined with meropenem has a synergistic effect on carbapene-resistant A baumannii, which can provide a basis for clinical treatment of drug-resistant bacterial infection.