Laser ranging uses laser as light source to measure distance. According to the working mode of laser, it can be divided into continuous laser and pulsed laser. Gas lasers such as He-Ne, Ar-ion, Krypton, Cadmium, etc. work in continuous output state and are used for phase laser ranging. Double heterostructure GaAs semiconductor lasers for infrared ranging: solid-state lasers such as ruby and neodymium glass are used for pulsed laser ranging. Compared with photoelectric rangefinder, laser rangefinder can not only work day and night, but also improve the ranging accuracy and significantly reduce the weight and power consumption, making it possible to measure the distance to long-distance targets such as artificial earth satellites and the moon.