Abstract: Based on the results of single factor experiments, the yield of polysaccharides was taken as the response, the ultrasonic-assisted extraction of polysaccharides from Guiqi-mango peels optimized by response surface methodology were carried out. The antioxidant activities of polysaccharides were then studied by free radical scavenging effects and total reducing power. The results showed that the optimized extraction process of polysaccharides were as follows:Temperature 68℃, liquid-material ratio 73:1 mL/g, ultrasonic power 620 W, ultrasonic time 20 min. Under the optimized conditions, the average extraction yield was 13.64%±0.12%, which had a relative error less than 3%with the expected yield of 14.06%. Clearance rates on·OH, O₂^-·, ABTS radical were 52.41%, 83.47%, 59.10% when the polysaccharides concentration was 4.3 mg/mL, and the total reducing power was 0.455.It showed that polysaccharides from Guiqi-mango peels had a good antioxidant activity which would be stronger with higher concentration.