The hot water extraction of schisandrae chinensis polysaccharide under different conditions was studied. The crude polysaccharide was eproteinized by sevage method. The scavenging ability of schisandrae chinensis polysaccharide against hydroxyl free radical was researched. The effect of different extraction temperature， solid-liquid ratio and extraction time on extraction yield was researched by single factor and response surface analysis. The results showed that the maximum extraction yield was 16.13% with solid-liquid ratio of 1∶30 under 85 ℃ for 3h. The crude polysaccharide solution was treated by sevage method repeatedly for 5 times， the clearance rate against protein could reach 92.58%， while keeping the polysaccharide in the maximum limit. The result of antioxidant performances showed that as the concentration of fructus schisandrae chinensis polysaccharide was 10mg/mL and the processing time was 1h， the clearance rate against hydroxyl free radical was 96.61%， which was much better than that of Vc.