Objective: To study the antimicrobial activity of different extracts of Trapa acornis against SA

MRSA and ESBLs-SA in vitro. Method: The MIC (Minimun Inhibitory Concentration) of different extracts of T. acornis against SA

MRSA and ESBLs-SA were detected by K-B method

and The IC50 (half maximal Inhibitory Concentration of a Substance) of different extracts of T. acornis against SA

MRSA and ESBLs-SA were detected by solution culture method. Result: The petroleum ether (TASPE)

EtOAC (TASEA) and n-butyl alcohol (TASBU) extracts exhibited significant inhibitory effects. TASPE showed the best antimicrobial activity of SA

MRSA and EsBLs-SA with IC50 value of 0.81

0.62

0.34 g·L-1 respeetively. Conclusion: Different extracts of T. acornis have the antimicrobial activity.