Abstract: In order to study the antioxidant activity of the oligosaccharide of Black Berry pectin,their radical scavenging activities were evaluated. After the enzymolysis of the extracted Black Berry pectin,different oligosaccharide fragments were obtained with graded ethanol precipitation. In vitro antioxidant activities of that oligosaccharide were evaluated by the DPPH radicals,ABTS radicals,and hydroxyl radical scavenging activity.The results indicated that the oligosaccharide obtained with 4 times of ethanol could scavenge DPPH radicals with ABTS radicals with IC50 values of 0.59 mg/m L and 4.75 mg/m L,respectively. By contrast,the oligosaccharide obtained with 10 times of ethanol showed relatively high scavenging activity on DPPH radicals and ABTS radicals with IC50 value of 0.40 mg/m L and 2.79 mg/m L,respectively. The oligosaccharide of Black Berry pectin exhibited significant antioxidant activity,and the scavenging activity on DPPH radicals and ABTS radicals presented a quantity-effect relation with the concentration of oligosaccharide.