Objective To analyze the clinical effect of narrow-band ultraviolet therapeutic apparatus in patients with psoriasis. Methods A total of 76 patients with psoriasis admitted to our hospital from February 2021 to February 2023 were selected as the research objects. They were divided into control group and experimental group by random number table method, with 38 patients in each group. The control group was treated with compound glycyrrhizin injection, and the experimental group was treated with narrow-band ultraviolet therapeutic apparatus. The biochemical indexes, inflammatory factor levels and quality of life were compared between the two groups. Results After treatment, the VD level in the experimental group was higher than that in the control group, and the ESM-1 level in the experimental group was lower than that in the control group (P <0.05). After treatment, the levels of TNF-α, CRP, IL-6 and IL-17 in the experimental group were lower than those in the control group (P <0.05). The quality of life scores of the experimental group were higher than those of the control group (P <0.05). Conclusion The effect of narrowband ultraviolet therapeutic apparatus in the treatment of psoriasis is significant, which can improve the expression level of positive factors such as VD, stabilize the inflammatory state, and play a therapeutic role. It is worthy of clinical application.