Abstract: Polysaccharides from Flos Sophora were obtained and determined by hot water extraction and ultrasonic extraction, ethanol precipitation and phenol- sulfuric acid method respectively. And antioxidant activity of the polysaccharides in virto was investigated by using reducing power, superoxide radical assay, DPPH· scavenge, activity and hydroxyl radical assay, using Vitamin C and BHT as a positive control.The results showed that the yield of Flos Sophora crude polysaccharide derived from ultrasonic extraction increased by 21.6% compared with the hot water extraction. The scavenging activity of free radical, concentration from 0.125 mg / m L to 2.0mg / m L, VC>polysaccharides of ultrasonic extraction > polysaccharides of hot water extraction > BHT.The scavenging activity of polysaccharides of ultrasonic extraction to superoxide radical assay ( scavenging rate, 70.78%) and hydroxyl radical assay ( scavenging rate, 75.34%) was higher than polysaccharides of hot water extraction ( scavenging rate, 62.28% and 70.45%, respectively) , and lower than VC ( scavenging rate, 98.21% and 94.53%, respectively) .Based on the above results, we conclude that crude polysaccharides from Flos Sophora has antioxidant activity, and the crude polysaccharides of extracts of different methods from Flos Sophora were promising free radical scavenger and antibacterial activity.