Laser hair removal is a kind of permanent hair removal method which is commonly used. Its principle is to act on the hair follicle and the tissues around the hair follicle through selective photothermal action to destroy the growth center of the hair, so that the hair cannot grow again and thus achieve the purpose of permanent hair removal. Therefore, as long as the laser hair removal method is correct, the hair removal is complete, and the number of times of hair removal is sufficient, it can be maintained for life. The specific number of laser hair removal treatment is related to many factors such as skin condition, hair removal area and hair type. Because the hair follicles have anagen, resting and dormant phases, the laser can only work on the hair follicles in the anagen phase, the other two phases do not work, so theoretically at least 3 or more treatments are needed, in practice it may be 5-6 times, or even more. Even if there is a very small amount of residual hair, it is still in a very fine and soft, light-colored state, and the final result is more satisfactory. There are some hairs that are really not good for hair removal using laser, such as male beard and female lip hair, which are related to sex hormone level and need to increase the number of times of hair removal to ensure the effect of hair removal. Other parts such as armpit hair, chest hair, abdominal hair, including the hair on the limbs, these parts of the hair after a course of laser hair removal, the effect is more durable.