The present invention belongs to the field of pharmaceutical chemistry, and disclosed are two crystal forms of Childamide, that is, Chidamide crystal form A and Chidamide crystal form B, and the method for preparing the new crystal forms of Chidamide. The Chidamide crystal form A and Chidamide crystal form B of the present invention can be used for preparing drugs for treating diseases related to cell differentiation and proliferation.
