Facial pigmented nevus, appearing malignant signs of treatment is not timely, will appear facial disfigurement or tumor metastasis, endangering life. Pigmented nevus appearing the following indicators, alert to malignant changes, timely to the hospital excision and pathological examination 1, diameter greater than 6mm, 2, edge asymmetry, 3, uneven color, 4, local itching, bleeding, satellite foci, short-term rapid growth. Treatment principle: 1, small feasible laser treatment, 2, large surgical excision and pathology examination, to exclude malignant What parts are prone to malignant transformation: nose, neck collar, belt area, palms of the hands, feet and other easy to chafing parts. Laser treatment has a certain recurrence rate.