Abstract： Objective： To observe the clinical effect of Xiaoyin capsules on the adjuvant treatment of psoriasis vulgaris with blood heat syndrome and its effect on the score of Psoriasis Area and Severity Index(PASI) and skin barrier function. Methods： A total of 108 patients with psoriasis vulgaris with blood heat syndrome were selected and divided into the observation group and the control group according to random number table method，with 54 cases in each group. The control group was treated with Yujin Xiaoyin tang，and the observation group was additionally treated with Xiaoyin capsules based on the treatment of the control group. The changes of inflammatory factors，including interleukin-2(IL-2)，interleukin-4(IL-4)， interleukin-10(IL-10) and γ-interferon(IFN-γ)，the PASI score and skin barrier function in both groups were compared before and after treatment，and the clinical effects and incidence of adverse reactions were evaluated. Results：The total effective rate was 96.30% in the observation group，higher than that of 83.33% in the control group，the difference being significant (P＜0.05). After treatment，the PASI scores and the IFN-γ levels in both groups were decreased when compared with those before，and the PASI score and the IFN-γ level in the observation group were lower than those in the control group(P＜0.05). After treatment，the levels of serum IL-2，IL-4 and IL-10 in the two groups were lower than those before treatmen，and the above levels in the observation group were lower than those in the control group(P＜0.05). After treatment，the TEWL values in the two groups were decreased when compared with those before treatment， and the TEWL value in the observation group was lower than that in the control group(P＜0.05). The corneous water content and sebum content in the two groups were increased when compared with those before treatment， and the corneous water content and sebum content in the observation group were higher than those in the control group(P＜0.05). Conclusion：Xiaoyin capsules has an ideal clinical effect on the adjuvant treatment of psoriasis vulgaris with blood heat syndrome，which can effectively improve