Nevus is generally a general term for “mole” disease, its color varies, lesions are spots, plaques, papules and patches, including pigmented nevus, nevus of Ota, halo nevus, Mongolian spots and other diseases. 1. Pigmented nevus: it is caused by benign proliferation of melanocytes. Clinically, it is mainly divided into intradermal nevus, junctional nevus and mixed nevus with different clinical manifestations. 2. Nevus of Ota: the cause of the disease is not clear for the time being, it is mostly related to genetic factors, and it occurs in the periorbital area, nose, forehead and other places. Patients will have centimeter-sized pigment spots with blue-gray or green-gray color. 3. Halo nevus: the cause of the disease is not clear, may be related to autoimmune system disorders and other factors, the patient’s skin will appear oval hypopigmented spots, the center of the nevus can be seen a pigmented nevus. 4. Mongolian spots: the cause of the disease is mainly related to hereditary factors, and it occurs in the buttocks and other parts of the body. Patients will appear round, oval and other patches, the color more gray-green, dark blue and so on. There are many reasons that lead to the appearance of nevus, it is recommended that patients go to the hospital to clarify the cause of the disease.