Melasma is one of the most common cosmetic skin diseases in oriental women, with a prevalence of 30%-70%, and is more prevalent in young and middle-aged women, and also in men. The cause is not fully understood, and although there are more treatment methods, the clinical treatment is not satisfactory. At present, it is thought to be related to endocrine disorders, oral contraceptives, antiepileptic drugs, topical glucocorticoids, genetic factors, oxygen free radicals, ultraviolet radiation, serum copper levels, tyrosine metabolism disorders, improper use of cosmetics, phototoxic drugs, dry skin, poor sleep, systemic diseases (thyroid diseases, gynecological diseases, liver diseases) and mood swings, among which endocrine disorders, genetic factors, ultraviolet radiation are the main causes. UV radiation is the main cause of the onset of the disease.