Abstract： Psoriasis is a complex polygenic disease with high incidence,and can occur under many inducements.Phototherapy is effective for the treatment of psoriasis,especially refractory plaque psoriasis at specific sites.At present,phototherapy protocols for psoriasis mainly includes ultraviolet A,ultraviolet B and excimer laser alone or in combination with various drugs.Generally,patients with mild to moderate psoriasis are managed by phototherapy alone,while those with moderate to severe psoriasis,especially those with poor response to conventional treatments,are treated with the combination of phototherapy and drugs,and attention should be paid to adverse reactions to combined therapy.In clinic,the efficay of phototherapy is associated with various factors such as age at onset,lesional sites and clinical type of psoriasis.