Method for extracting and separating high-purity polysaccharide from plant flowers

A method for extracting and separating high-purity polysaccharides from plant flowers is disclosed and comprises the following steps: (1) drying fresh plant flowers, adding an alcoholic solution withthe concentration of more than or equal to 80%, soaking, and carrying out residue-liquid separation, (2) removing the solvent from the obtained alcoholic solution to obtain a crude flavone product, removing the solvent from the obtained residues, adding a salt solution with the saturation degree of 35-57%, and repeatedly extracting to obtain an extracting solution, (3) combining the extracting solutions, and sequentially passing through cation exchange resin, anion exchange resin and lower column water to obtain a crude polysaccharide aqueous solution, (4) adding n-butyl alcohol into the crudepolysaccharide aqueous solution for repeated extraction, combining n-butyl alcohol layer solutions and concentrating to obtain a water-soluble saponin product, combining water layers, concentrating and evaporating water, addi