The invention discloses a method for extracting high-purity 
astragaloside from 
astragalus mongholicus, and belongs to the technical field of biological medicines. The method comprises the following steps: (1) taking a ground 
astragalus mongholicus root, adding water, carrying out 
reflux extraction for 2-4 times at normal temperature, combining 
water extraction solutions, concentrating until the density is 1.2-1.3, adding 
ethanol, stirring for depositing fully, centrifuging, filtering and collecting a supernatant solution; (2) placing the supernatant solution into a reaction kettle, adding 10% of alkali solution by 
mass concentration for adjusting the pH value to be 10, reacting for 8-12 h at the temperature of 40 DEG C, adding 
dilute acid for adjusting the pH value to be neutral, extracting by using normal 
butanol and concentrating; and (3) adding 
ethyl acetate into a normal 
butanol concentrated solution for extracting, and re-crystallizing by using 
methanol to obtain a white 
crystal, which is a target product-
astragaloside. The method is simple and easy to implement, the yield of a product is more than 0.08%, the purity of the product reaches more than 98%, the product has no chemical 
reagent residues, and the extraction process is environment-friendly and low in requirement on 
reagent and equipment and is suitable for large-scale industrial production.