Abstract:The extraction process of polysaccharides from Chenopodium quinoa by enzymatic and ultrasound co-extraction was optimized.The best auxiliary enzyme was cellulase and the optimum dosage was 3%through the experiments. The extracting parameters including extraction temperature 65 ℃，ultrasonic time 18 min，material liquid ratio of 1 ∶33（g/mL）were optimized by using response surface methodology design based on the single-factor experiments.And the extraction rate of Chenopodium quinoa polysaccharide was 68.08%，which was close to the theoretical value of 70.78%.The crude polysaccharides extracted under the optimal conditions above were studied in vitro after deproteinization. The antioxidation experiment showed that the effect of Chenopodium quinoa polysaccharide on hydroxyl radical scavenging activity was significant，the effect of free radical scavenging on DPPH and ABTS+were not significant.In addition，the research showed that Chenopodium quinoa polysaccharide had a certain inhibitory effect on the activity of alpha-amylase，and the inhibition ratewas up to 27.29 %. It showed that Chenopodium quinoa polysaccharide had certain effect in reducing blood sugar.