This paper introduces the quantitative analysis of mineral phase in Sialon-bonded corundum brick by X-ray diffraction (XRD) method,and points out that the molecular formula of Sialon-bonded phase is Si3Al3O3N5,and obverses the crystal and morphology of Sialon-bonded phase with scanning electron microscopy (SEM) and energy dispersive spectrometer (EDS).The results show that the contents of mineral phases in Sialon-bonded phase,silicon carbide and  corundum phases in Sialon-bonded corundum brick is quantitatively analyzed by X-ray diffraction method,which are consistent with the results of DIFK laboratory in Europe and completely meet the requirements,indicating that X-ray diffraction method can be used for quantitative analysis of mineral phases in Sialon-bonded corundum brick.