Abstract: Using K fluorescence X-rays, we conducted diffraction efficiency experiments on LiF220 crystals at energies of 23.3 keV and 31 keV. By adjusting the Bragg angle of the incident monochromatic X-rays, we measured the diffracted monochromatic X-rays. The experimental results showed that the crystals produced relatively complete diffraction peaks at both energies. Under irradiation at energies of 23.3 keV and 31 keV, maximum diffraction efficiencies of approximately 2.46% and 1.33% were obtained at incident angles of 10.8° and 8.1°, respectively, which are consistent with theoretical values. This study provides experimental data support and reference for research in materials science and other related fields. Measurements of diffraction efficiency can be used to verify the accuracy of experimental results, providing a tool to test experimental conditions and data interpretation, ensuring the reproducibility and reliability of the study.