When treating vitiligo with ultraviolet light, if oral, intramuscular or topical psoralen is used at the same time, it can increase the sensitivity of skin to ultraviolet light, improve melanocyte synthesis and keratin-forming cells’ ability to transport melanin, promote pigment regeneration of white spots and improve the treatment effect. There are more types of psoralen, mainly 8-methoxypsoralen, 5-methoxypsoralen and 3-methoxypsoralen. The roots, stems, leaves or fruits of many plants contain psoralen, such as Chinese herbal medicine Psoralen, Serpentine, Fennel, Cassia, Angelica, Angelica, Dahurica, Solanum, North Saxifrage, Qianglong, Qianhu, Fructus, Fig, Tiger’s stick, Cyperus, Maitake, etc. The skin is most sensitive to ultraviolet light 1~3 hours after oral administration of psoralen, and the effect time can last for 8~12 hours, so appropriate topical application or oral administration of the above drugs before UV irradiation treatment can increase the therapeutic effect.