Laser beam collimation method

The invention relates to a laser beam collimation method. The collimation method comprises the following steps that the spot diameter of a laser beam emitted by a laser is obtained, a diaphragm with the proper aperture of a light through hole is selected according to the spot diameter, and the aperture of the light through hole meets the requirement that a diffraction ring can be formed after the laser beam passes through the aperture. Installing a laser, a diaphragm and a photosensitive device, enabling the laser to emit a laser beam by taking the target on the photosensitive device as a target, and enabling the laser beam to form a plurality of concentric diffraction rings on the photosensitive device after the laser beam passes through a light through hole of the diaphragm. Adjusting the distance between the photosensitive device and the light through hole to adjust the circularity of the diffraction ring, and enabling the absolute value of the difference value of the exposure values of any two points on t