This article studied the extraction,purification and antioxidant activity of polysaccharide extracted from the Dioscorea nipponica, Optimizesed the extraction process of water soluble polysaccharide extraction and ultrasonic-assisted extraction,we got get a certain amount of purified polysaccharide. The main results of this study are as follows.1. The extraction process of polysaccharide from Dioscorea nipponica,Two different methods of water extraction, ultrasonic extraction were respectively adapted to ex...