NOVELTY - Preparation of porcine bile ursodeoxycholic acid as raw material, involves: (1) extracting as raw material porcine bile mother liquid of bilirubin, using sodium hydroxide, adding calcium chloride solution, water washing, adding propionic acid/acetic acid, heating, adding in water; (2) dissolving formed chenodeoxycholic acid in solution of acetone and water, and adding oxidant, chenodeoxycholic acid into 70-lithocholic acid; (3) using secondary butanol, sodium metal under reflux, reducing 70-lithocholic acid into ursodeoxycholic acid and chenodeoxycholic acid mixture; and (4) purifying.    USE - For preparation of porcine bile ursodeoxycholic acid as raw material (claimed).    ADVANTAGE - The method reduces the preparation cost; and has high economic benefit. In preparation of ursodesoxycholic acid from chenodeoxycholic acid, calcium chloride is used as precipitating agent, which avoids environment pollution caused by the conventional barium precipitating agent, and at the same time, simplifies the precipitation process.    DETAILED DESCRIPTION - Preparation of porcine bile ursodeoxycholic acid as raw material, involves: (1) preparation chenodeoxycholic acid: extracting as raw material porcine bile mother liquid of bilirubin to obtain total bile acid, adding ethanol to dissolve, using sodium hydroxide to adjust pH to 7.2-7.5, adding calcium chloride solution to complete the precipitation, water washing precipitate to obtain chenodeoxycholic acid calcium salt, adding 50% propionic acid or 60% acetic acid, 40-50 degrees C heating to completely dissolve, then adding in water to precipitate chenodeoxycholic acid; (2) oxidation: dissolving the chenodeoxycholic acid in the mix solution of acetone and water, and then adding oxidant, the chenodeoxycholic acid into 70-lithocholic acid; (3) reducing: using secondary butanol as solvent, sodium metal as reducing agent under reflux, reducing the step (2) 70-lithocholic acid into ursodeoxycholic acid and chenodeoxycholic acid mixture; (4) purification: placing the step (3) of ursodeoxycholic acid and chenodeoxycholic acid mixture in organic solvent, at 75-85 degrees C low temperature reaction with silicification agent, to generate ursodesoxycholic acid silicon ether solid precipitate, and then the solid at 40-50 degrees C low temperature and acid reaction, to obtain ursodesoxycholic acid pure product.    DESCRIPTION OF DRAWING(S) - The figure shows a flow chart of the process for preparation of porcine bile ursodeoxycholic acid. (Drawing includes non-English language text).