The appearance of dark spots on the legs should be considered as a variety of conditions. Firstly, it is considered to be the possibility of seborrheic keratosis, which is commonly known as age spots, the specific cause of which is unknown and may be related to skin aging, genetic factors, tumor factors, viral infection, ultraviolet radiation, etc. Usually, no treatment is needed, and those who feel that it affects their appearance can choose to use 40% hydrogen peroxide solution topically, and if necessary, laser or liquid nitrogen freezing can be chosen to remove it. Secondly, it is considered to be post-inflammatory pigmentation, and the main reason for its occurrence is that the inflammatory reaction reduces the sulfur hydrogen group in the skin and increases the tyrosinase activity, resulting in local pigmentation, which usually does not need treatment, and those who have the desire for treatment can choose to use topical hydroquinone cream, etc. If the effect of topical medication is not good, laser treatment and mesotherapy can be chosen.