() quaternary ammonium salt precipitation: according to the properties of different molecular weight polysaccharides with different solubility in a certain concentration of salt solution, various polysaccharides were separated. The neutral salts that are often added to polysaccharides are NaCl, KCl, NH4, SO4, etc. the separation method is essentially one of the step precipitation methods; (3) metal complex method: the precipitation is formed by the complex of polysaccharides with copper, barium, calcium and lead ions. The commonly used complexing agents include the reagent of Fei Lin, copper chloride, barium hydroxide and lead acetate. (4) gel column chromatography, also known as gel filtration, is a chromatographic method for separating substances according to their molecular weight. The common column chromatography is gel column chromatography and cellulose anion exchange column chromatography. Gel column chromatography is based on the principle of molecular sieve, which can be separated according to the size and shape of the separated molecules.