The invention relates to a preparation method of 
calcitriol which is a compound material, belonging to the technical field of preparation of 
drug synthesis and 
organic compound synthesis. In the invention, the 
calcifediol is taken as 
raw material, a majority of produced impurities in the 
chemical reaction process are removed through medium-pressure 
liquid phase chromatography, wherein 
calcifediol carried out sulfonylation and ring closing on 
toluene, and the medium-pressure 
liquid phase chromatography is used for removing the impurities; products carry out oxidation reaction, medium-pressure 
chromatographic column separates and removes the impurities, ring opening is carried out, medium-pressure 
liquid phase is added for coarsely separating stereoisomeride, and at last the products separated by high-pressure liquid phase 
chromatography is hydrolyzed and refined to obtain the 
calcitriol. The invention is reasonably selected, comprehensively applies the advantages of the medium and 
high pressure liquid phase chromatography, has simple detaching method, can effectively remove the impurities, thoroughly separates the stereoisomeride, has high purity of the 
calcitriol obtained from separation, has a productive rate of 40 percent, high yield and low cost, shortens production period, is suitable for 
industrial scale, has application prospect, and provides a time-saving, economic and efficient method for the separation and the preparation of chiral compounds.