Provided are novel crystalline forms of Lanifibranor (Referred to as "Compound I") and preparation methods thereof, pharmaceutical compositions containing the crystalline forms, and uses of the crystalline forms for preparing pan-PPAR agonists drugs and drugs for treating NASH. Compared with prior arts, the provided crystalline forms of Compound I have one or more improved properties, which solve the problems of the prior art and is of great value to the optimization and development of the drugs.