In 1912, Laue et al. predicted by theory and confirmed by experiment that diffraction can occur when X-ray meets crystal, proving that X-ray has the property of electromagnetic wave, which became the first milestone in X-ray diffraction.

When a monochromatic X-ray is incident on a crystal, the X-rays scattered by different atoms interfere with each other, resulting in strong X-ray diffraction in some special directions. This is the basic principle of X-ray diffraction.

X-ray diffraction is reliable when used for qualitative analysis and accurate when used for quantitative analysis, and has the characteristics of simple and rapid detection, high sensitivity, multi-component and multi-crystal detection at one time. However, the sensitivity of X-ray diffraction phase analysis method is not high for the phase with less content in mixed urinary stones, so it should be combined with other methods.

The advantages of X-ray diffractometer: high sensitivity to measure the strength of diffraction lines; The inspection method is simple and rapid; Sample analysis can be performed at high or low temperatures; Suitable for the determination of continuous phase transition samples. The disadvantages are :① powder method is affected by reagents, and sometimes the quantitative is not accurate. ② The required instruments are more expensive, and the maintenance conditions are higher.