Chrysanthemum is the dry capitulum of compositae chrysanthemum morifolium, and its chemical composition mainly includes terpenoids, flavonoids and polysaccharide compounds.The chrysanthemum polysaccharide has obvious immunomodulatory and antitumor activity, but further research about the structure characterization, biological activity and structure-activity relationship are still unclear so far.So chrysanthemum dry capitulum is extracted by boiling water and ethanol precipitation, getting crude polysaccharide (JHA).