Abstract: The study researched the polysaccharides content and antioxidant activities of Portulace oleracea L. by using ultrasonic extraction method to extract the polysaccharides of the root, stem, leaf and bud. Results presented that the polysaccharides extraction rate in stem was the highest, which reached to 7.65%.The scavenging rates of hydroxyl radical and superoxide anion were 91.42% and 78.02%, when the extract concentration of leaf reached to 9 mg/m L and 10 mg/m L, respectively.When the concentration of polysaccharide extracts in root was 10 mg/m L, it had the highest scavenging capability to DPPH free radical, which could reach to 99.41%.The polysaccharide extracts in root area had high reducibility.When the concentration was 5 mg/m L, the maximum reducibility could reach to 0.80. In the different radical systems, the scavenging capacity to the hydroxyl radical, superoxide anion, DPPH free radicaland reducing ability of polysaccharide extracts from different organs of Portulace oleracea L.were extraordinary, meanwhile, the antioxidant capacity of polysaccharide extracts had a dose-effect relationship with the mass concentration.