Abstract: OBJECTIVE To establish a method for the determination of the contents of irbesartan polymorphs and to provide technical support for the quality control of crystal forms. METHODS X-ray powder diffraction method was used to characterize form A and B of irbesartan. A standard curve method was developed by using the characteristic peak ratio of form A at 4.65° 2θ and form B at 7.99° 2θ as the quantitative parameters, and the content of form B was calculated by the standard curve. RESULTS The curve of form B in the mixtures of form A and B was linear over the range of 2%-50% with r of 0.999 5, the instrument precision was 4.7%, and the concentration of LOD was 1.12%(S/N=4.4). CONCLUSION The established method is accurate, simple, and can be used to determine the contents of form B in the mixtures of form A and B.