There are types of pigmented nevi, such as intradermal nevus, junctional nevus, mixed nevus, etc., and giant nevus, blue nevus, juvenile melanoma, etc. Some types can become malignant under certain conditions and deserve attention.　Pigmented nevi mostly occur on the face, neck and back and can be seen in any normal human body. They may be present at birth or may appear gradually in the early postnatal years. Most grow slowly or persist for many years without change, but spontaneous regression rarely occurs. Surgical and non-surgical treatments are available. The treatment is effective. Pigmented nevi are congenital benign tumors composed of pigmented cells, most of which are benign; in later stages, there are malignant cases. Once a pigmented nevus becomes malignant, its malignancy is extremely high and its metastasis rate is the fastest, and the treatment is not ideal. The disease can be seen in all parts of the skin, with the face and neck, chest and back being the preferred sites. A few occur in the mucous membranes, such as the oral cavity, labia, and lid conjunctiva. For certain pigmented nevi that have a high incidence of junctional nevi and those with signs of malignant transformation, timely excision is required.