Sodium valproate crystal form as well as preparation method and application thereof

The invention discloses a sodium valproate crystal form II as well as a preparation method and application thereof, wherein characteristic absorption peaks appear at diffraction angles of (2theta)=6.3-6.5 DEG, 7.12-7.32 DEG, 7,3-7.5 DEG, 16.95-17.15 DEG, 18.15-18.35 DEG, 18.88-19.08 DEG and 19.17-19.37 DEG in a powder x-ray diffraction pattern of the crystal. The sodium valproate crystal form II provided by the invention has the advantages that the hygroscopicity is significantly reduced and lower water content of the product is guaranteed to ensure that the quality of the sodium valproate is more stable in storage period; while the hygroscopicity is reduced, the dissolution time of the product is significantly shortened and the dissolvability of the product is improved to ensure that the curative effect and very good safety of the sodium valproate are guaranteed in clinical application, the injection pain is also significantly relieved, compliance of patients is increased during treatment and very good clini