Abstract: Background: The oxidative stress induced cell damage triggers both the physiological process of aging and many pathological progressions that eventually lead to serious health problems. Lots of researches exhibited that some polysaccharides have been demonstrated to play an important role as free radical scavenger for the prevention of oxidative damage in living organisms. So the purpose of the present investigation was to elucidate the isolation of the polysaccharide from Sarcodia ceylonensis and evaluate its antioxidant activities. Materials and Methods: Three polysaccharide fractions (SCP-40, SCP-60 and SCP-80) from Sarcodia ceylonensis were obtained by using the method of water-extraction and ethanol-precipitation. In order to evaluate the antioxidant activity in vitro of these polysaccharides, the radicals scavenging activity against ABTS, DPPH and hydroxyl radicals was determined. Results: The results showed SCP-40 exhibited strong scavenging effects on these radicals. For in vivo assays, the polysaccharide SCP-40 was found to increase the levels of antioxidant enzymes superoxide dismutase and to decrease the malondiadehyde content in blood serum. Conclusion: The polysaccharide SCP-40 from Sarcodia ceylonensis should be explored as a novel potential antioxidant.