Objective To investigate the application effect of Kaixuan Xiaoyin decoction combined with calcipotriol ointment in patients with psoriasis vulgaris. Methods A total of 110 patients with psoriasis vulgaris admitted to Ningxia Hospital of Integrated Traditional Chinese and Western Medicine from May 2023 to May 2024 were selected as the research subjects. According to the random number table method, they were divided into the control group and the observation group, with 55 patients in each group. The control group was treated with calcipotriol ointment, and the observation group was treated with Kaixuan Xiaoyin Decoction combined with calcipotriol ointment. The Psoriasis Area and Severity Index (PASI) score, clinical efficacy and glomus diameter were compared between the two groups. Results After treatment, the scores of infiltration, erythema and scale in the two groups were lower than those before treatment, and those in the observation group were lower than those in the control group (P <0.05). The total effective rate of treatment in the observation group was 94.55%, which was higher than 81.82% in the control group (P <0.05). After treatment, the glomus diameter in the two groups was smaller than that before treatment, and that in the observation group was smaller than that in the control group (P <0.05). Conclusion The application of Kaixuan Xiaoyin decoction combined with calcipotriol ointment in patients with psoriasis vulgaris has a definite effect. It can improve the total effective rate of clinical treatment, accelerate the regression of skin lesions, and relieve the clinical symptoms, which is worthy of clinical application.