In this experimentation the method of DPPH was adopted to do research about antioxidant activity of polysaccharides of different sweet potatoes. The results showed that antioxidant activity of polysaccharides from different sweet potatoes was obviously different in optimum condition. The antioxidant activity of polysaccharide of nine species of sweet potatoes from high to low were American black potato (the repression rate was 98.31%), fruit potato (the repression rate was 96.61%), German black potato (the ...