The invention relates to a method for preparing silybin. The method comprises the following process steps: crushing silybin seeds into 20 to 40 meshes, and
degreasing the crushed silybin seeds thrice by using n-
hexane; refluxing and extracting degreased coarse materials by using dilute
ethanol; concentrating the extract under reduced pressure till the extract has no
ethanol smell, extracting the concentrate by using
ethyl acetate, stirring and
drying ester phase and
silica gel, then injecting a dried product to a column, eluting the dried product by using
benzene or
benzene-
ethyl acetate, collecting the elute by sections, combining the elute to obtain main elute component of the silybin, concentrating the elute under reduced pressure, dissolving the elute in
ethanol solution, adding
active carbon into the solution, stirring the solution, decolorizing the solution for 0.5 to 1 hour, filtering the
active carbon from the decolorized solution, concentrating the decolorized solution under reduced pressure to 40 to 60 percent of the primary volume, cooling the concentrate to separate out crystals, crystallizing the crystals by using hot ethanol, and repeating the
crystallization step for 2 to 4 times to obtain the silybin. The method for producing the silybin has the advantages of simple process, low
solvent toxicity, low production cost, and easy realization of industrialization.