Nevus of Ota was first reported and named by Masao Ota in Japan in 1938. It is a pigmented lesion caused by genetic or certain intrauterine causes of abnormal differentiation of melanocytes in the skin, involving the skin in the distribution area of the trigeminal nerve (mainly the 1st and 2nd branches) of the face, and often spreading to the sclera and other tissues. Clinically, it is characterized by brownish-blue patches or patches of skin around the eyes and face, so it is also known as brownish-blue nevus of the palate and ocular dermal melanocytosis. According to clinical studies, 50% of nevus of Ota are hereditary. This is mainly related to the genes of the parents of the affected children. Timely treatment of nevus of Ota can reduce the probability of heredity to a certain extent. The formation of birthmarks, such as nevus of Ota, can also be caused by fetal injury and the accidental consumption of food containing contaminants by pregnant women. Nevus of Ota occurs because some melanocytes fail to cross the junction of dermis and epidermis when migrating to the epidermis, and stay in the dermis or below the dermis for a long time. It can be divided into: 1. Light type: (1) Light orbital type: light brown spots, limited to upper and lower eyelids nevus of Ota. (2) Light cheekbone type: light brown spots, limited to the cheekbone. 2.Medium type: dark blue to purple-brown, distributed on eyelids, cheekbones and nose root. (3) Heavy type: dark blue to brown, distributed in the first and second branches of the trigeminal nerve innervation area. 4. Bilateral type: both cheeks. It can also be classified according to other categories: according to color: brown type, cyan type. According to the histological characteristics: superficial in type: pigment cells are located in the superficial layer of the dermis, and are mostly brown clinically; deep in type: pigment cells are located in the deep layer of the dermis, and are mostly cyanotic; diffuse type: pigment cells are located in the whole layer of the dermis, and are mostly purplish-blue. According to the age, it is divided into: early type: within a few years after birth; late type: after puberty. At present, the treatment of nevus of Ota mainly includes surgery, freezing and laser treatment. Laser treatment is the most widely used because of its precise efficacy and mild side effects. Nevus of Ota cannot fade away on its own, and it will seriously affect the beauty of patients’ appearance and cause psychological disorders, so it should be treated by laser as soon as possible.