Abstract: The pumpkin polysaccharide was extracted by water-extract and ultrasonic method,respectively.The pumpkin AP1 polysaccharide was obtained from the precipitate with cetyltrim-ethlammonium bromide(CTAB).The phenanthroline-Fe²⁺ reaction system was used to estimate the activity of pumpkin polysaccharide against hydroxyl radicals.The result showed that the pumpkin polysaccharide had the ability to scavenge hydroxyl radicals.The scavenging effects increased with the increasing of concentration.The scavenging ability of the water-extract pumpkin polysaccharide was much better than that of those extracted by ultrasound on hydroxyl radicals.It was demonstrated that the pumpkin polysaccharide had antioxidative property,and the water-extract pumpkin polysaccharide showed the better scavenging ability remarkably.