Objective To study the antioxidant activity of Reed rhizome.Methods The prepration,purification and determination of polysaccharides in Reed rhizome were investigated.The optimal technical parameters of extracting polysaccharides from Reed rhizome were determined through orthogonal test.The antioxidative activity of Reed rhizome Polysaccharides were studied and compared with Vc including the experiment of inhibiting the formation of hydroxyl radical,reducing power and inhibiting formation of lipid peroxidation.Results The result showed that the optimal technical parameters were liquid—solid ratio l:3 and the extracting time 8minutes under max power through microwave assistant extraction.The concentration of polysaccharide in Reed rhizome was 0.798%.Polysaccharides had obvious reducing capauty and was equal to Vc.Scavenging capability to hydroxyl radical of Polysaccharides was lower than Vc.When Abs was lower than 0.88,the inhibition to lipid peroxidation was equal to polysaccharide.Conclusion Microwave method is helpful to extract the polysaccharides in the Reed rhizome,and it demonstrates the antioxidant activity of the polysaccharides.