Congenital melanocytic nevus (CMN) is very common, with an incidence of about 1% in newborns. 2. International grading standard of CMN: small pigmented nevus is <1.5cm in diameter (also 5cm), medium-sized pigmented nevus is 1.6-19.9cm, and >20cm or >5% of body surface area is called giant pigmented nevus. Although the incidence of melanoma in children has slightly increased this year, the overall rate is still extremely low. If the lesions become larger, have uneven color, and have blurred edges or changes in adulthood, the possibility of malignant transformation should be alerted. 4. CMN can be treated comprehensively: at present, laser and electrocautery are the most widely used techniques, but the recurrence rate is relatively high. Surgical excision is the most complete and has a low recurrence rate, but it cannot be widely used, especially for multiple scattered small CMN. 5.The recurrence or not of scar edge after excision of congenital pigmented nevus is related to the new satellite nevus. 6. One-time complete excision or fractionated excision is widely used internationally for the treatment of CMN, which requires clean excision of the lesion and sufficient depth (even deep to the fascia), and recurrence after CMN excision is rarely reported. For CMN of moderate size or larger, the incidence of melanoma can be reduced by staged excision or one-time excision followed by repair with skin grafting or transfer flaps, and both procedures have no effect on the recurrence rate of CMN. Staged resection (surgery every 3-6 months) reduces the risk of organ deformation and displacement and facilitates the repair of the patient’s shape and function, and is most suitable for the treatment of CMN with a diameter of 5-8 cm (or a similar proportion of pediatric CMN). 7. The malignancy rate of severe atypical hyperplastic pigmented nevus (DN) is 1 in 10,000, and re-excision should be performed with positive cut margins to prevent recurrence and malignant transformation. However, the recurrence rate of benign and moderate CN is extremely low, about 3%, even if the scraping biopsy is incomplete or the margins are positive, and the need for re-excision (enlargement to 2-5 mm of the margins) for benign and mild to moderate DN with positive margins is not great. 8. Similarly, giant nevi (some scholars call them preneoplastic lesions) should be excised early and followed up for life, but prophylactic excision is not recommended for medium-sized or small CMN, and even if excision is performed, the risk of malignant transformation cannot be 100% removed. In conclusion, the treatment of CMN should be individualized by taking into account the size and location of the lesion, the risk of malignancy, and the psychological aspects of the patient and family.