Abstract： Objective： To observe the clinical effect of the therapy of modified Zhibai Dihuang Tang combined with western medicine on children with allergic purpura with syndrome of vigorous fire due to yin deficiency. Methods：A total of 86 children with allergic purpura were randomly divided into the observation group and control group， with 43 cases in each group. The control group was treated with conventional western medicine，and the observation group was additionally treated with conventional western medicine combined with modified Zhibai Dihuang Tang. The Chinese medicine syndrome scores， T lymphocyte subsets，including CD3 +，CD4 +，and CD19 +，immunoglobulin and inflammatory factors were compared between the two groups before and after treatment. The clinical effects and recurrence were compared between the two groups. Results：After treatment，the observation group total effective rate was 93.02% were higher than control group 74.42%(P＜0.05). After treatment，the scores of skin purpura，joint pain， abdominal pain，fever of palms and sole，hot flushes on the cheeks，low-grade fever and night sweats， vexation and restless sleep in the two groups were lower than those pre- treatment(P＜0.05)， and the scores of the above Chinese medicine syndromes in the control group were higher than those in the observation group(P＜0.05). After treatment，compared with pre-treatment the serum levels of CD3+ and CD4+ in the two groups were increased(P＜0.05)，but the levels of CD19+ were decreased(P＜0.05)，and the improvement of the above levels in the observation group was better than that in the control group(P＜ 0.05)；compared with those pre-treatment，the serum levels of immunoglobulin A(IgA)，immunoglobulin M(IgM)，immunoglobulin G(IgG)，tumor necrosis factor-α(TNF-α)，interleukin-4(IL-4) and interleukin-12 (IL- 12) were significantly decreased(P＜0.05)； in the control group the levels of immunoglobulin and inflammatory factors were higher than those in the observation group(P＜0.05). After three months of follow- up，the observation group recurrence rate was 12.50% lower the control group 40.62%(P＜0.05). Conclusion： The therapy of modified Zhibai Dihuang Tang combined with western medicine has a significant clinical effect on allergic purpura， which can effectively improve the immune level of children， reduce the levels of inflammatory factors and the recurrence rate.