Abstract: In order to expend the utilization of Agaricus bisporus waste stipe,using A. bisporus waste stipe as raw materials,the effects of ultrasonic power,ultrasonic extraction time,liquid-solid ratio,ultrasonic extraction times and ethanol content on the yield of polysaccharides from A. bisporus stipe were investigated by single factor experiment. Technology parameters were optimized by orthogonal test. And the antioxidant activities of polysaccharides in vitro were also assayed. Results showed that the optimum extraction conditions were as follows:ultrasonic power was 700 W,ultrasonic extraction time was 50 min,liquid-solid ratio 20:1 (mL·g^-1),2 times of ultrasonic extraction and volume of ethanol to extract for precipitation was 4 times. The yield of polysaccharides could be 5.35 g·100 g^-1. As compared to ascorbic acid,the polysaccharides of A. bisporus stipe had a powerful scavenging ability on DPPH·,a lower scavenging ability on hydroxyl radicals and reducing power.