Objective: To evaluate antioxidant activity of Desmodium heterocarpon in vitro. Method: 1-diphenyl-2-picrylhydrazyl (DPPH) radical scavenging

diamonium salt (ABTS) radical scavenging and ferric reducing antioxidant power (FRAP) assay were used to evaluated D.heterocarpon with BHT as positive control. Result: Antioxidant activity of D.heterocarpon was good.Ethyl acetate extract of D.heterocarpon showed the DPPH radical scavenging (IC50=35.66 mg·L-1)

ABTS radical scavenging (IC50=8.49 mg·L-1)

and ferric reducing antioxidant power (TEAC=756.20 μmol·g-1) and those were higher than that of other extracts.But it was still inferior to positive control BHT (IC50=3.69 mg·L-1

IC50=6.64 mg·L-1 and TEAC=4 997.76 μmol·g-1

respectively). Conclusion: Ethyl acetate extract showed the best antioxidant activity in three extracts.