Abstract: The orthogonal experiment was used to optimize the extraction process of polysaccharides from Pholiota namek by ultrasonic synergistic.The DPPH·, O₂～-·and·OH scavenging ability and reducing power of polysaccharides from Pholiota namek were studied.The polysaccharide yield was determined by thephenol-sulphuric acid method with hot water extraction after ultrasonic.Through the single factor test and orthogonal, the effect of polysaccharide yield by ultrasonic power, ultrasonic time and ratio of water to raw material were researched.The best process was 80Hz, 15min and 20∶ 1, respectively.The results indicated that Pholiota nameko polysaccharide had better antioxidant activity via evaluating free radicalscavenging and reducing power.