The invention discloses a novel method for preparing medicinal despun hydroxyl methionine calcium. Pure water and acid are added to feed grade liquid methionine to carry out warming and backflow, after cooling, calcium hydroxide is added to the mixture to regulate the pH value, an organic solvent is added to the mixture, a small amount of solid impurities are filtered, vacuum concentration is carried out after adding pure water into the filter liquor, purified water is added, calcium hydroxide is added to the mixture to regulate the pH value after warming, the organic solvent is added to the mixture dropwise after activated carbon decoloration, cooling and centrifugation are carried out after dropwise adding is completed, crude products of the despun hydroxyl methionine calcium are obtained, and the crude products of the despun hydroxyl methionine calcium are refined in a mixed solvent of pure water and the organic solvent to obtain the refined products of the despun hydroxyl methionine calcium. According to the technology, raw materials are easy to obtain, the technology is simple, used solvents can be recycled to use, the content and purity of obtained products are quite high, the crystalline form is quite good, stirring of high rotating speed is not needed, materials are easy to separate and dry, the phenomena of caking and hardening in material drying will not be generated, course products in a mother solution can also be recycled, and the novel method for preparing the medicinal despun hydroxyl methionine calcium is suitable for industrial mass production.