Flavonoids was extracted and purified from Hong Guo Ginseng. The antioxidant activity of purified flavonoids,Vc,combination solution of flavonoids and Vc( 1∶ 1) were investigated by testing scavenging effects of ·OH、O2-·,reducing ability of Fe3 +and inhibition of the peroxidation oflipids. The results showed that at the same concentration of 0. 65 g / L,the scavenging rate of flavonoids to ·OH and to O2-· were 21. 07% and 24. 23%. The scavenging rate of combination solution to · OH and O2-· were 25. 50% and 29. 00% respectively,both better to Vc. But Vchad the strongest reducing capacity to Fe3 +among three antioxidants. When the concentration was 0. 28 g / L,the protection rate of combination solution was 96. 30% to oil and 74. 83% to fat,respectively,being excellent among three antioxidants. The statistics analysis results indicated that the combination solution had a greater cooperative antioxidant activity than Vc or flavonoidsindividually.