Common moles include pigmented nevus, nevus of Ota, nevus of Ito, pigmented gross epidermal nevus, freckle-like nevus, non-pigmented nevus, and bright red nevus. Pigmented nevus is also called chromatophobic nevus, spot nevus or nevus, and can be divided into junctional nevus, intradermal nevus and mixed nevus. Junctional nevus is mostly found on the palms of hands, soles of feet, lips of mouth and external genital area, with flat or slightly high surface, size between 1-2 mm, light brown, brown-black or blue-black. There is a possibility of cancer, which can occur as melanoma; intradermal nevus has smooth surface and clear boundary. It is larger than 1 mm, grows in patches, and is flat or slightly elevated. The color is dark and uniform, light brown, dark brown or inky black. Generally, no cancerous changes occur; mixed nevus: it is a mixture of the above two kinds, generally like an intradermal nevus, which can also become cancerous because it has the components of junctional nevus. Nevus of Ota is a pigmented birthmark characterized by greenish-brown nevus in the area around the eyes, also known as palatal brownish-brown nevus, which is a blue-brown patchy damage that affects the sclera and the facial skin innervated by the trigeminal nerve. About half of the patients are found to have the disease at birth, but some of them start to find it in childhood, and some patients only gradually show it in adolescence. It appears as a patch composed of brown, gray and blue spots with unclear borders, and the spots in the lesion can be monochromatic or have both of the above colors, and the shades vary. Ito nevus, also known as blue-brown nevus of the deltoid muscle, was described by Ito in 1954 as a pigmented spot similar to nevus of Ota, distributed on the shoulder and upper arm innervated by the posterior supraclavicular nerve and the lateral brachial nerve. The distribution by nerve suggests that melanocytes may originate from local nerve tissue. Ito nevus belongs to the category of nevus of Ota, and some cases can be accompanied by nevus of Ota. It occurs in people of color, such as oriental and black people, and 65% of patients have it at birth, while the rest appear between the ages of 10 and 20. In addition to affecting the appearance. Pigmented gross epidermal nevus, also known as Becker’s nevus, develops in adolescents and is usually found on the shoulders, scapulae area and forehead. Freckle-like nevus, also known as nigra, can be distributed in any part of the skin, as well as at the junction of the skin and mucous membrane or the conjunctiva of the eye, manifesting as brown or dark brown spots, some slightly elevated, round, generally about the size of a pinpoint to sesame. The surface of the spots may have slight flaking, but their delicate skin texture remains unchanged. The pigmentation is uniform, and the edges gradually fade and approach the normal skin color. The distribution is also sparse and scattered, and the color does not deepen and the number does not increase after sun exposure. Pigmentless nevi occur in infants at birth or shortly after birth and expand proportionally with age. The damage is often distributed along the nerve segments and appears as limited or generalized hypochromic spots with irregular, non-pigmented edges, which are not as obvious as vitiligo. Sometimes the white spots are mixed with light brown corn to lentil freckle-like spots, feeling normal, if the pressure on the surrounding skin to make it ischemic, then the boundary between the affected area and the surrounding skin still exists. It is one of the types of nevus, and the lesions remain unchanged for life. Bright red nevus, also known as capillary dilation nevus or wine-like nevus, often occurs at birth or soon after birth as light red, dark red or purple-red patches, not higher than the skin surface, easy to fade when pressed, irregular in shape, with clear boundaries, mostly seen behind the occiput, nose, forehead and between the eyebrows, and some cases fade on their own around 1 year old. The traditional treatment measures for various nevi are: freezing, chemical corrosion, electrocoagulation, microwave, grinding, radiation or isotope treatment, surgical excision or skin implantation. At present, new laser treatment measures include: common pigmented nevus can be treated with ultra-pulsed CO2 laser and Q-switched laser; nevus of Ota and nevus of Ito can be treated with 532nm, 694nm, 755nm, 1064nm, 2940nm wavelength lasers, but to achieve the ideal effect, more than 3-7 treatments are needed, and each treatment interval is about 3-6 months; pigmented gross epidermal Pigmented nevus can be treated with ultra-pulsed CO2 laser and bait laser; freckle-like nevus can be treated with ultra-pulsed CO2 laser and Q-switched laser; treatment of erythematous nevus is the same as treatment of hemangioma; non-pigmented nevus can be treated with laser grinding, followed by autologous epidermal transplantation. At the same time, precautions for various nevi include: if a pigmented nevus is suspected to be malignant, it must be surgically removed and sent for disease examination, and laser treatment is forbidden; junctional nevus is recommended to be surgically removed, and laser treatment is cautious; laser treatment is forbidden for pregnant women, diabetic patients, patients suspected to have skin cancer and keloid; after laser treatment, keep the local area clean and dry, and the scab will fall off by itself; during the recovery period, pay attention to sun protection, and prohibit smoking, alcohol and stimulating food.