The present invention provides an (R)-4-hydroxy-2-oxo-1-pyrrolidineacetamide crystal form, which has diffraction peaks when 2θ is 12.423±0.2°, 16.465±0.2°, 17.344±0.2°, 21.889±0.2°, and 25.054±0.2°. The present invention can promote synthesis of phosphorylcholine and phosphoethanolamine and promote cerebral metabolism, has a stimulating effect on the specific central nervous pathway through the blood-brain barrier, and has special biological activity in the fields of sedation, anti-epilepsy, etc. The (R)-4-hydroxy-2-oxo-1-pyrrolidineacetamide crystal form in the present invention has a melting point peak temperature of 133.1±2°C and a solubility in water of greater than or equal to 100 mg/mL, dissolves fast in water, provides high bioavailability, good stability, and good particle fluidity, is suitable for production of pharmaceutical preparations and storage and transportation. The crystal form is suitable for preparation into a variety of pharmaceutical compositions, and can be prepared into a variety of preparations, such as tablets, capsules, dripping pills, sustained-release controlled-release preparations, lyophilized powder injections, etc. The preparation method of the present invention is simple and suitable for industrial production.
