The graphite curved crystal monochromator is installed in front of the X-ray detector, which monochromatizes the X-rays passing through the receiving slit and only detects the K α characteristic X-ray diffractometer accessories of the X-ray spectrum. By using this device, continuous X-rays, K β characteristic X-rays, and fluorescent X-rays can be completely eliminated, enabling high signal-to-noise ratio X-ray diffraction analysis. When copper target X-ray tubes are used in conjunction with corresponding monochromators, fluorescent X-rays generated from Mn, Fe, Co, Ni based samples can be eliminated, making them suitable for analysis of various samples.