This paper focuses on the polysaccharide withdraw in sweet potato leaf and stem with hot-water-dipping method,the decolorization research,and the polysaccharide content determination with anthrone color method.The result indicated that,the best method is to decolorize with hydrogen peroxide solution after adjusting pH to the neutrality in the withdraw process,and that the polysaccharide content in sweet potato tender stem is 6.12%(the highest),the old stem 4.47%,the leaf 2.09%(the lowest).