Abstract: A method for the detection of γ-FeOOH in iron oxide desulfurizing agent has been established using X-ray diffraction analysis.The integral intensity of the quantitative diffraction peak of γ-FeOOH exhibited a good linear relationship with its percentage in the range of 30% to 100%.The linear correlation coefficient was 0.997 7, which provided a research idea for the determination of FeOOH content in different crystal types.A sample of γ-FeOOH desulfurizer with known content was also determined with a relative error of 3.7%.Using this method, the polymorphic mixture of FeOOH in the desulfurizer sample can be analyzed qualitatively and quantitatively, which is of great significance for the further study of the polymorphic mixture of FeOOH in the desulfurizer.The method is accurate, reliable, easy to operate and feasible to some extent.It provides a reference for the qualitative and quantitative analysis of γ-FeOOH in iron oxide desulfurizer.