The present invention herein provides a method for highly efficientlypreparinghigh purity crystals of 2-amino-2-[2-[4-(3-benzyloxyphenylthio)-2-chloro-phenyl]-ethyl]-1,3-propanediol hydrochloride:((see above formula)The method comprises the following steps:(1) dissolving 2-amino-2-[2-[4-(3-benzyloxyphenylthio)-2-chlorophenyl]ethyl]-1,3-propanediol in a mixed solvent comprising ethanol and ethyl acetate withstirring at atemperature ranging from 50 to 90°C, to thus prepare a solution of2-amino-2-[2-[4-(3-benzyloxyphenylthio)-2-chlorophenyl]ethyl]-1,3-propanediol；and then(2) adding hydrochloric acid having a concentration ranging from 1 to 12mole/L tosaid solution with stirring at a temperature ranging from 50 to 90°C,to thus crystallizethe hydrochloride of 2-amino-2-[2-4-(3-benzyloxyphenylthio)-2-chlorophenyl]ethyl]-1,3-propanediol,wherein, in the step (1), a volume amount of the mixed solvent ranges from 20to50 times the mass of 2-amino-2-[2-[4-(3-benzyloxyphenylthio)-2-chlorophenyl]ethyl]-1,3-propanediol； and a mass ratio of ethanol/ethyl acetate ranges from 1/4 to 1/1.
