This invention provides a method for preparing cycloastragenol monoglucoside CMG (cycloastragenol-6-O-β-D-glucoside), comprising the steps of: a. using astragaloside IV or Astragali extracts prepared by a conventional method as raw materials and adding an appropriate solvent thereinto to form a raw material solution b. adding hydrolase and allowing for hydrolysis at a constant temperature to obtain a hydrolysate c. separating the hydrolysate with macroporous adsorption resin and d. obtaining the product by purification and separation. The present invention further provides cycloastragenol-6-O-β-D-glucoside prepared according to the method of this invention as well as its use in the preparation of a medicament for treating cardiovascular diseases and pharmaceutical compositions comprising the same.
