[Objective]The flavonoids were extracted from ginseng root and its antioxidant activity was studied.[Method]The method of ethanol reflow and polyamide enrichment were adopted in the extract of the flavonoids from ginseng root.The antioxidant of the flavonoids from ginseng root was tested with DPPH method,Fenton method and rats feeding.[Results]When the concentration of the ginseng root flavonoids was over 0.5 mg/mL,the scavenging rate of the DPPH free radical was more than 80%and 0.6 mg/mL,the hydroxyl free radical,as high as70.8%.The activity of SOD in rat brain could increase over 17.97%after the rat was fed with the flavonoids at the concentration of 80-120mg/kg per day for five weeks.[Conclusion]The ginseng root flavonoids had a strong scavenging effect on DPPH free radical and hydroxyl free radical in vitro and also an intensifying effect on the activity of SOD in SD rat brain in vivo. [Objective] The flavonoids were extracted from ginseng root and its antioxidant activity was studied. [Method] The method of ethanol reflow and polyamide enrichment were adopted in the extract of the flavonoids from ginseng root. The antioxidant of the flavonoids from ginseng root was tested. [Method] with DPPH method, Fenton method and rats feeding. [Results] When the concentration of the ginseng root flavonoids was over 0.5 mg / mL, the scavenging rate of the DPPH free radical was more than 80% and 0.6 mg / mL, the hydroxyl free radical, as high as 70.8%. The activity of SOD in rat brain could increase over 17.97% after the rat was fed with the flavonoids at the concentration of 80-120mg / kg per day for five weeks. [Conclusion] The ginseng root flavonoids had a strong scavenging effect on DPPH free radical and hydroxyl free radical in vitro and also an intensifying effect on the activity of SOD in SD rat brain in vivo.