Abstract:To optimize the extraction technology for Chinese yam polysaccharides by response surface method，and preliminary researched the DPPH free radical scavenging capacity （DPPH·），hydroxyl radical（OH·），superoxide anion radical （O2-·）and alpha glucosidase inhibitory activity.In order to evaluate the indicators，the effects of ultrasonic extraction temperature，extraction time and ratiliquid-solid ratio on Chinese yam polysaccharide yield were compared by Box-Behnken design-response surface method.The optimal ultrasonic extraction technology were determined as follows：extraction temperature of 66℃，extraction time for 26 min，liquid-to-material ratio of 22 ∶1（mL/g），under which the yield of polysaccharide was 9.34%.Polysaccharides from different habitats have an inhibitory effect on alpha glucosidase activity，and the inhibition rate increases with the increase of polysaccharide concentration.The antioxidant activity test showed that polysaccharide had a significant scavenging effect on DPPH·，OH·and O2-·，and showed a certain concentration dependence.The content of polysaccharides in Henan province was the highest，the inhibitory effects on alpha glucosidase activitie and the scavenging activities of DPPH·and OH·were significant.