The principle of diode laser hair removal treatment is based on selective photothermal decomposition. The melanosomes in the hair follicle can selectively absorb the energy of the laser. The laser energy emitted by the machine is easily absorbed by the colored hair follicle without damaging the epidermal tissue. The energy emitted by the laser is absorbed by the hair and the pigment in the hair follicle. It is converted into heat, thus increasing the temperature of the hair follicle. When the temperature rises to a certain level, the hair follicle will be irreversibly damaged, and the hair will lose its original environment and be completely removed.