Abstract: ObjectiveThe extraction process of polysaccharides from Hibiseu smanihot L.was optimized,and its antioxidant activity was investigated,in order to provide basis for research and utilization of polysaccharides from H.smanihot L.MethodTaking extraction rate of H.smanihot L.polysaccharides as index,and on the basis of single factor experiment,the extraction technology assisted by ultrasonic was optimized by L9(33) orthogonal test.The antioxidant activities of H.smanihot L.polysaccharides were evaluated through scavenging experiment on DPPH free radical and the hydroxyl free radical (· OH).ResultThe three factors affecting ultrasonic-assisted extraction of H.Smanihot L.polysaccharides were in order as follows:ultrasonic time>material-liquid ratio>ultrasonic temperature.The optimum extraction process parameters of polysaccharides were as follows material-liquid ratio 1∶50,ultrasonic time of 30 min,ultrasonic temperature 50 ℃.Under such condition,the extraction rate reached 22.32%.Free radical scavenging experiment showed that scavenging effects of H.Smanihot L.polysaccharides towards DPPH free radical and · OH varied according to the dosage.ConclusionThe optimized extraction process of H.Smanihot L.polysaccharides is simple,convenient and feasible.And H.Smanihot L.polysaccharides has strong antioxidant activity.This processing technique can be applied in extraction and development of H.Smanihot L.polysaccharides.