Preparation method of 17 alpha-hydroxyl steroid ester

The invention discloses a preparation method of a steroid, and particularly relates to a preparation method of 17 alpha-hydroxyl steroid ester. 17 alpha, 21-dyhydroxyl steroid reacts with orthoester to form a steroid intermediate containing 1, 3-dioxane-5-cyclohexanone, and then 17 alpha-hydroxyl steroid ester is obtained through hydrolysis. Compared with the prior art, the preparation method has the advantages that highly amyctic trifluoroacetic anhydride is avoided, the reaction condition is mild, a solid acid can be adopted for catalytic hydrolysis, the catalytic acid is recycled, so that environmental protection is facilitated, and the method has low pollution, simple technology and mild reaction condition, and is suitable for industrial production.