There are many kinds of lasers used for treatment in dermatology, from power to power, there are high-powered lasers and low-powered lasers, high-powered lasers generally have a destructive effect on the tissue, and can even be used as laser knives to cut the tissue, such as the laser sword in the movie “Star Wars” is a fantasy of this type of laser, low-powered lasers are generally used to improve and promote blood circulation, such as today’s children’s Toys are generally small lasers, can hit a beam of red laser, energy is very small, can be driven by a few small batteries, shining on the skin will not feel stronger than the feeling of flashlight irradiation, there is no effect on the human body. From the point of view of treatment results, the laser can be divided into non-selective treatment laser and selective treatment laser, non-selective laser, as the name implies treatment is non-selective, that is, in the treatment, in addition to the treated lesions, other non-lesion parts will be eliminated without any spared. The result of this laser treatment is certain to leave scars, and this laser is currently the most used laser at all levels of hospitals. Selective treatment lasers, also known as micro/non-invasive laser treatments, are highly selective in their treatment, destroying only the target tissue while leaving no or only minor damage to non-target tissues, thus leaving essentially no scars during treatment.