The 308nm excimer laser is currently an effective alternative to all traditional psoriasis treatments. From the current research the efficacy is certain, and relative to local treatment, systemic medication and traditional phototherapy, it has its unique advantages. 308nm excimer laser selectively irradiates the affected skin, so that the healthy skin is not exposed to irradiation, which effectively reduces the exposure of the overall skin, and reduces the incidence of skin cancer. In addition the new therapy has a short treatment period and quick effect. Although it has been applied to the clinic for a short period of time, the biological effect, therapeutic mechanism and adverse effects of long-term use are still not very clear, but with the progress of related research and the accumulation of clinical experience, its therapeutic mechanism will be further elucidated, and the clinical treatment will be more and more perfect.