First of all, the action of the laser is achieved by heating the target tissue, which is known as the photothermal effect. The basic histological change of skin aging is the reduction of dermal collagen fibers, which leads to skin atrophy, manifested as increased wrinkles and skin laxity. Secondly, a large number of experiments have demonstrated that after the dermal tissue is heated. New collagen can be produced by collagen cells directly or by activating a series of related cytokines. In this way, we can achieve the purpose of “skin rejuvenation” by choosing a laser that heats the dermis directly without destroying the epidermis. Currently, there are several lasers used for non-invasive aesthetic treatments with the aim of effectively heating the dermis and stimulating its collagen cells to produce more collagen fibers, thus rejuvenating the collagen layer and achieving skin rejuvenation.