Abstract:Natural polysaccharides have good biological activity and function，while microalgae have the characteristics of fast growth，strong adaptability，large-scale reproduction under artificial cultivation，small occupation area，and low production cost.In order to dig more microalgae polysaccharide resources，Chlorococcum sp.GD polysaccharides were separated by traditional hot water extraction method.The crude Chlorococcum polysaccharides were purified by DEAE-52 cellulose column chromatography and Sephadex G-150 column chromatography，and their antioxidant activities were studied.The results showed that：1）the yield of crude polysaccharide was 6.07 %，and four components，CPP-I，CPP-II，CPP-III and CPP-IV，were obtained by fractional purification with high purity；2）Chlorococcum sp.GD polysaccharides had obvious removal effects on DPPH and Hydroxyl radicals，with removal rates exceeding 90%and 70%respectively，and the effect of CPP-IV was better than that of crude polysaccharides；3）Chlorococcus sp.GD polysaccharides had a certain removal effect on superoxide anions and ABTS+radicals，with removal rates exceeding 50 % and 27 %，and the reducing power was 0.404.The results indicated that the purified polysaccharides had good antioxidant activity，and the removal rate increased with the increase of polysaccharide concentration，though they were lower than the clearance rate of VC.