Abstract: To evaluate the antioxidant activity of green coffee bean extract, five kinds of systems including the total antioxidant capacity, DPPH free radicals scavenging activity, ABTS free radicals scavenging activity, ferric reducing ability and ferrous ions chelating activity were employed for the experiment. The results indicated that green coffee bean extract in a certain concentration range showed a strong total antioxidant capacity that was very significantly higher than BHT and VC ( p <0.01) , and that was further proved by a strong DPPH radical ( IC50 ( 0.072 ± 0.003) mg /mL) , ABTS radical ( IC50 ( 0.22 ±0.01) mg /mL) scavenging activity and a strong ferric reducing ability. Nevertheless, green coffee bean extract did not show ferrous ions chelating activity.Green coffee bean extract had strong antioxidant activity, thus it is a potential natural antioxidant.