Method for preparing chenodeoxycholic acid and ursodesoxycholic acid magnesium trihydrate

The invention discloses a method for preparing chenodeoxycholic acid and ursodesoxycholic acid magnesium trihydrate, which is characterized in that the method comprises the following step: mixing chenodeoxycholic acid, ursodesoxycholic acid and magnesium salts in acetone-water solution containing triethylamine for taking reaction to prepare the chenodeoxycholic acid and ursodesoxycholic acid magnesium trihydrate. In the method provided by the invention, sodium hydroxide used in the original process is replaced by triethylamine, and meanwhile, acetone-water mixed solvents are used, so colloid substances do not occur any longer, and inorganic salt impurities in products are obviously reduced.