Objective:To observe the effect on cytokines and hemorrheology of Yangyin Qingre Huoxue recipe in treatment of the patients with recurrent aphthous ulcer. Methods126 cases of patients with recurrent aphthous ulcer were randomly divided into the observation group (65 cases), and the control group (61cases). The control group was treated with Cetylpyridinium chloride buccal tablets, the observation group was treated with Cetylpyridinium chloride buccal tablets Yangyin Qingre Huoxue recipe,all of the two groups were treated for 2 months.To observe the cflinical effect and the change of cytokines and hemorrheology of the two groups.  Results:①The total efficiency of the observation group was 92.31%, the total efficiency of the control group was 70.49%,the difference was statistically significant (P<0.05); ②After treatment, the levels of IL-2、INF-γ were significantly increased and IL-10、IL-6 were significantly decreased with before,and the difference of the two groups was statistically significant (P<0.05);③After treatment, the whole blood viscosity and plasma viscosity of the observation group were decreased (P<0.05) with before, and that was lower than the control group (P<0.05).  Conclusion:Yangyin Qingre Huoxue recipe can improve the clinical efficacy of RAU, which may be related to regulation of immune function, improve hemorrheology.