The present disclosure relates to novel crystalline forms of NBI-98854 (as shown in formula I), preparation process and use thereof. The crystalline forms of NBI-98854 provided by the present disclosure, named as Form CS1 and Form CS2, can be used for preparing drug product treating tardive dyskinesia. The crystalline forms of NBI-98854 provided by the present disclosure have pharmaceutically acceptable solubility and hygroscopicity, good stability and are stable during storage, thereby avoiding changes in drug solubility, dissolution rate, bioavailability and efficacy due to polymorph transformation. This provides a new and better choice for the preparation of drug product containing NBI-98854, which has significant value for future drug development.
