Abstract: Abstract:The antioxidant activities of different polar solvent extracts of Polygonum multiflorum were studied and the correlation between activity and polyphenol content was investigated. Method:The polyphenols from Polygonum capitatum were extracted by macroporous resin,and the samples were extracted with different polar organic solvents. The samples were divided into petroleum ether phase,chloroform phase,ethyl acetate phase,n-butanol phase,aqueous phase with different polar solvent extracts. The total polyphenol content of different polar solvent extracts was determined. Scavenging activities of the extracts on the DPPH free radicals,hydroxyl radicals and ABTS free radicals were studied. The relationship between antioxidant activity and polyphenol content was analyzed. And the ethyl acetate extract was identified by HPLC. Result:The antioxidant activity of ethyl acetate was the best,and IC₅₀ of the DPPH,ABTS and hydroxyl radicals were correlated with the content of polyphenols(r=-0.988,r=-0.742,r=-0.563). Quercetin was the main antioxidant component of ethyl acetate phase. Conclusion:Ethyl acetate phase extract could be used as important part seperated antioxidant substances and polyphends were the main active ingredients of antioxidant activity.