Pigmented dermatoses are a common group of skin diseases, including nevus cell nevi (acquired nevi and congenital nevi), epidermal melanocyte damage (e.g. freckles and nevi), and dermal melanocyte damage (e.g. blue nevi, nevus of Ota, and zygomatic brownish nevi). Although most of them do not have much impact on human health, they often bother patients due to cosmetic problems or fear of malignant changes. This article provides a brief introduction to common pigmented diseases and their treatment principles to raise public awareness of the treatment methods for such diseases. The treatment of pigmented skin diseases generally follows the treatment principles of mastering the indications and paying attention to the cosmetic effects. Only those with higher possibility of malignant transformation and serious cosmetic effects should be treated, such as congenital nevus, spotted nevus and nevus of Ota, while common nevus, Spitz nevus, halo nevus and common blue nevus can be treated without treatment as long as they are not in easily damaged parts, such as long beard; freckles, simple nevus, solar nevus and zygomatic brown nevus can generally be left untreated unless the patients strongly request it; a disease can be treated by different methods If a disease can be treated by different methods, try to choose the method with good cosmetic effect, such as various nevus cell nevi and deep damage such as increase of dermal melanocytes, if treated by destructive treatment methods such as microwave and freezing, it is easy to leave obvious scars or pigmentation, so it can not be applied as much as possible, instead, surgical treatment or new high-energy pulsed laser treatment can be used, and attention should be paid to the direction of incision when surgical excision to reduce scars. Drug corrosion, especially “crystal cream” containing strong alkali or strong acids such as sulfuric acid, nitric acid and glacial acetic acid, should be avoided because they often leave obvious scars and pigmentation. For the treatment of epidermal melanocyte damage (such as freckles and freckle-like nevus), Q-switched pulsed dye laser (585 nm), Q-switched Q-switched Nd:YAG laser (532 nm), Q-switched ruby laser (694 nm), Q-switched emerald laser (755 nm) can be used for treatment. The treatment of freckles with strong pulsed light (also known as photorejuvenation or compound color light) can also achieve good results with 3-5 times as a course of treatment, and it does not affect normal work. Treatment of dermal melanocyte damage, such as nevus of Ota, which seriously affects beauty and has almost no satisfactory treatment method in the past, has been treated with Q-switched pulsed laser since the 1990s, which has made a breakthrough in the treatment of nevus of Ota. Most of the treatments are satisfactory with 3-5 times; blue nevus can be treated with Q755 laser or surgical excision. Nevus cell nevus, also called chromatophores or nevus, is the most common kind of benign tumor in human body. It may be a local concentration of melanocytes due to accidental abnormalities during the movement of pigment cells from the neural crest to the epidermis, which becomes a nevus of color. It can be seen clinically at any age and tends to increase significantly during development. The lesions may appear on all parts of the body surface and may take the form of spots, papules, papillomatous, verrucous nodules, dome-shaped, polyp-like, or tipped lesions. Some lesions may have short, thick black hairs running through them. Treatment is firstly considered surgical excision. Small lesions can also be treated by vaporizing laser (such as CO2 laser), but it may leave scarring. The hairs on the surface of congenital pigmented nevus can be treated by laser hair removal, and pigment removal and hair removal can be carried out alternately; Q-switched laser has certain effect on congenital pigmented nevus with small area (within 50cm2), and the treatment can be done clinically on a trial basis, but there is a possibility of leaving scar after treatment; congenital giant nevus generally has the tendency of malignant transformation, so it is treated by surgical excision as much as possible. Due to the stimulation of external negative factors, nevus may become malignant, such as malignant melanoma. The following conditions should be noted: (1) Chromatophobic nevi usually appear before the age of 20-30, and the occurrence of new chromatophobic nevus damage at an older age should raise suspicion. (2) Any individual nevus that becomes darker or larger rapidly than other nevi should be taken seriously. (3) If the nevus is repeatedly infected or vulnerable to trauma, it should be removed, but there is no evidence for sure. (4) When a nevus recently increases significantly, especially asymmetrical, changes in color (red, white, blue, black), surface changes (scaling, erosion, moist, scab, ulcer or bleeding), pain or tenderness, satellite damage around it and enlarged lymph nodes belonging to it are signs of malignant change of nevus. (5) Any change of nevus on the extremities should be taken seriously. Generally speaking, junctional nevi are the most prone to malignant transformation, while intradermal nevi are the most stable. If malignant nevus is suspected, pathological tissue examination should be performed in time and surgical excision should be performed if necessary.