Ginseng polysaccharide extraction method

The invention discloses a ginseng polysaccharide extraction method. The ginseng polysaccharide extraction method comprises the following steps: 1), ginseng is extracted with alcohol, filter residues are extracted with water, and a filtrate is collected for standby application; 2), the filtrate is precipitated by ethanol, and a precipitate is obtained; 3), the precipitate is washed and dissolved in water, a product is washed again and dissolved in water, a product passes through a hollow fiber membrane with the molecular weight cut-off being 100,000, a first concentrated solution is collected and passes through a hollow fiber membrane with the molecular weight cut-off being 1,000,000, a second permeate liquid and a second concentrated solution are collected respectively, the second concentrated solution is collected and passes through a hollow fiber membrane with the molecular weight cut-off being 1,000,000, a third concentrated solution is collected and passes through a hollow fiber membrane with the molecular weight cut-off being 1,800,000, a fourth permeate is collected, the second permeate liquid and the fourth permeate liquid are combined, centrifuged and filtered, and a filtrate is collected for standby application; (5), activated carbon is added to the filtrate for decoloration, the mixture is filtered, a filtrate is taken and subjected to spray drying, and ginseng polysaccharide is obtained. The ginseng polysaccharide has good blood sugar reducing effect when taken orally.