The invention relates to a technology for extracting and separating active ingredients of traditional Chinese medicines, in particular to a method for extracting and separating high-purity 1-deoxynojirimycin from folium mori, which comprises the following steps of: extracting a
powder material by using an aqueous
solvent, filtering off dregs, and centrifuging the material to obtain extracting solution; concentrating the extracting solution until
ethanol does not exist, and filtering by using an
ultrafiltration membrane; regulating the pH to be 3.0-4.0 by using inorganic acid, precipitating, and centrifuging to removing impurities; applying acidified feed to a strong acid cation resin column, washing with water, and eluting by using
ammonia water; applying feed liquid to a porous resin column, washing with water, performing
gradient elution by using
ethanol with different concentrations, and collecting target eluent; concentrating the target eluent under reduced pressure, and
drying to obtain a crude product; dissolving the crude product by using absolute
ethanol, making the solution pass through an alkaline adsorbing column to remove impurities, and collecting
effluent liquid; and concentrating the
effluent liquid under reduced pressure, and performing normal temperature
crystallization and recrystallization to obtain the refined 1-DNJ product. In the whole technological process, except ethanol, other organic solvents are not used, the operation is safe, and the 1-DNJ content can reach 98.3 percent.