Purification method for sinistrogyration oxiracetam

Provided is a purification method for sinistrogyration oxiracetam. The method comprises the steps of adding sinistrogyration oxiracetam coarse products in water for dissolving, dropping organic solvent in solution to enable the solution to become turbid just, standing at 0-18 DEG C for 1-3 days, separating out colorless transparent crystals, filtering, washing by using ice water at the temperature of 0-5 DEG C in a top mode, and drying in a vacuumizing mode to obtain the sinistrogyration oxiracetam with high purity. By means of the corresponding purification process using water as the organic solvent in the purification method, 89% of purity of the sinistrogyration oxiracetam coarse products is effectively increased to 97.5-98.2% of high performance liquid chromatography (HPLC) purity, and the purity of the sinistrogyration oxiracetam is greatly improved. Simultaneously, the purification method is simple, mild in control conduction, low in cost of production and applicable to large-scale industrial production.