Abstract: Extracting polysaccharide from Chinese herbal medicine Angelica Sinensis,using concentrated sulfuric acid method to prepare sulfated angelica polysaccharide,selecting the degree of substitution as the index,optimized the sulfation process by single factor and orthogonal experiment:when the reaction temperature is 0 ℃,the reaction time is 2 h and the ratio of nbutyl alcohol to sulfuric acid is 1:3,the DS of samples reached 2.04,which is an ideal result.

Key words: Angelica sinensis polysaccharide, sulfated esterifying, the degree of substitution