Abstract: In order to improve the antioxidant activity of fig polysaccharides, ultrasonic pretreatment of polysaccharides solution was investigated. Based on the reduction ability and hydroxyl radical scavenging capacity, the effect of ultrasonic power, pretreatment time and the on /off time ratio on ultrasonic pretreatment efficacy were studied. The results showed that the optimum conditions of ultrasonic pretreatment were 600W of ultrasonic power, 90min of pretreatment time and 5 ∶ 2 ( s ∶ s) of ultrasonic on /off time ratio. Under the optimum conditions, the reduction ability and hydroxyl radical scavenging capacity of fig polysaccharides were up to 0.701 and 30.343% , respectively. Compared with the untreated fig polysaccharides, the reduction ability and hydroxyl radical scavenging capacity derived from ultrasonic-treated fig polysaccharides increased by 24.010% and 26.306% , respectively.