Abstract: Objective To explore the optimal irradiation scheme of narrow band ultraviolet irradiation by analyzing the different frequency and dose increment in the treatment of psoriasis vulgaris. Methods A total of 128 patients with psoriasis vulgaris recruited from March 2015 to June 2016 in Chinese PLA General Hospital were randomly divided into group A (0.04 J/cm² dose increment, irradiation once a day), group B (0.07 J/cm²dose increment, irradiation once a day) and control group (group C, 0.1 J/cm²dose increment, irradiation 3 times a week). All patients were treated by whole body NB-UVB radiation combined with kalbrometil ointment and halomethasone ointment. Age, disease course and severity index (PASI) score before treatment between the three groups showed no significant difference. The efficacy was evaluated according to the drop in proportion of psoriasis area and PASI at the 10th day and 20th day to calculate the improvement rate. The adverse reactions during irradiation were recorded. Results After 10 days treatment, the improvement rate of group B(47.81%±11.87%) was higher than that of group A (33.57%±7.30%) with statistically significant difference (P< 0.05), and both group A and group B had advantage over the group C (P< 0.05); After 20 days treatment, the improvement rate of group B(56.2%±19.8%) was still higher than that of group A (43.3%±19.5%) with significant difference (P< 0.05), while no statistically significant difference in the improvement rate was found between group A and group C (P=0.475). Conclusion The radiation protocol (0.07 J/cm²dose increment, once a day) is recommended as the first choice in the treatment of psoriasis vulgaris with narrow-band UVB due to its rapid onset, short duration and mild side effects.