Abstract:The ultrasonic-assisted extraction technology and antioxidant activities of polysaccharide from the leaves ofActinidia kolomikta（Rupr.et Maxim.）Planch were researched in this paper.Taking the yield of crude polysaccharide as the response value，on the basis of single factor experiment，the effect of ultrasonic-assisted extraction factors on polysaccharide were researched.A three-level-three-factor response surface methodology design was employed to optimize the three extraction variables and to determine the optimum technology.And the antioxidant capacity of the polysaccharide was assessed through DPPH radical scavenging test.The experimental results showed that the optimum technology was that the ultrasonic power was 989.61 W，the extraction time was 20 min，the extraction liquid-to-solid ratio was 80 ∶1（mL/g），under the condition the yield of the crude polysaccharide from the leaves ofActinidia kolomiktawas 5.59%.Setting ultrasonic power as 990 W，extraction time as 20 min and liquid-to-solid ratio as 80 ∶1（mL/g）to verify the optimum extraction technology，and the yield of the crude polysaccharide was 5.41%.The polysaccharide extracted from the leaves ofActinidia kolomiktahad effect of scavenging DPPH radical，and the ability of scavenging DPPH radical was proportional to the concentration of polysaccharide.