The raw polysaccharide and refined polysaccharide were prepared from the body wall of fresh starfish Asterina pectinifera. The scavenging capacity of the raw polysaccharide and refined polysaccharide on hydroxyl radical,DPPH radical and superoxide anion were detected using electron spin resonance (ESR). The result indicated that the polysaccharide from the body wall of fresh starfish Asterina pectinifera possessed a certain scavenging capacity. And this scavenging capacity was enhanced with concentration rising. The IC₅₀ values of three radical scavenging activities of raw polysaccharide were 59.56,27.29,31.36 mg/mL and the IC₅₀ values of three radical scavenging activities of refined polysaccharide are 44.96,13.97,3051 mg/mL. At the same concentration of polysaccharide powder, the scavenging capacities of refined polysaccharidewere stronger than the raw polysaccharide for hydroxyl radical, DPPH and superoxide anion scavenging abilities.