Abstract: X-ray powder diffraction technique is one of the main methods to study drug polymorphs. In the process of drug production, there would be a change of crystal type, only the qualitative analysis of the crystalline form has not satisfied the quality control requirements of modern medicine. In this paper, the application of X-ray powder diffraction technique in the quantitative analysis of polymorphic drugs is reviewed by consulting domestic and foreign literature. The crystalline state analysis of the drug by X-ray diffraction quantitative technology, will enable the drug polymorphism in the practical process more clearly elaborated and more reasonable control, so as to establish a scientific quality control system and strict quality standard of drugs.