Children’s body nevus that is pigmented nevus more, can be congenital or acquired nevus, for the skin melanocyte accumulation and become, in the youth can have batches of appear. Pigmented nevus is a benign proliferation composed of melanocytes, which can appear at any time from birth to postnatal period, and can increase in number with age, and is related to congenital heredity or developmental defects. The cause of congenital nevus of pigmentation is unknown and may be related to gene mutation during embryonic development. The important causes of acquired nevus are mainly related to ultraviolet irradiation, drugs, trauma, hormone level change and immunosuppression. When there is a mole on the skin, attention should be paid to reduce the friction and stimulation of the mole body to prevent malignant changes. For moles with irregular edges, large diameters or uneven colors, attention should be paid to observing them, and if there is any manifestation of rapid expansion, ulceration and bleeding, consult a doctor in time to make a clear diagnosis.