Abstract： Objective： To observe the effect mechanism of Wenjing Tongluo Powder regulating Treg/ Th17 cell balance for rheumatoid arthritis，and provide scientific basis for the clinical application of Wenjing Tongluo Powder for rheumatoid arthritis. Methods： Constructed a bovine type II collagen induced DBA/1 mice of collagen-induced arthritis (CIA)， and divided the successfully modeled mice into the CIA model group (Model group)， the methotrexate positive group (MTX group)， and the Wenjing Tongluo Powder group (WJTLS group). Clinical scoring evaluation was conducted on the severity of arthritis in mice； hematoxylin eosin (HE) staining was used to detect the pathological damage degree of arthritis in CIA mice； enzyme linked immunosorbent assay was used to detect antibody levels in CIA mice and levels of inflammatory cytokines IL-10 and IL-17 in lymphocyte culture supernatant； flow cytometry was used to detect the expression levels of total CD4+ T cells，Treg cells (CD4+ Foxp3+ T cells)，Th17 cells (CD4+ IL-17+ T cells)，and Th1 cells (CD4+ IFN-γ+ T cells). Results：Compared with those in the Model group，the joint index scores in the MTX group and WJTLS group were decreased on days 10，12，14，16，and 18 after administration (P＜0.05). Compared with those in the Model group， the proliferation of synovial tissue， cartilage and bone erosion were significantly reduced， the degree of inflammatory cell infiltration was significantly relieved，and the degree of joint surface damage was significantly alleviated in mice in the MTX group and the WJTLS group. The pathological scoring results showed that when compared with those in the Model group， the joint tissue pathological injury scores in mice of the MTX group and the WJTLS group were reduced (P＜0.05). Compared with those in the Model group， the serum IgG3， IgG2a， and IgG antibody levels of mice in the WJTLS and MTX groups were decreased， but the difference showed no significance (P＞0.05). Compared with those in the Model group， the level of IL-10 in the supernatant of mice spleen cell culture in the WJTLS group was increased (P＜0.05)，and the level of IL-17 was decreased (P＜0.05). The results of flow cytometry analysis showed that WJTLS intervention could reduce the absolute number of CD4+ T cells in the spleen of CIA model mice (P＜0.05)， upregulate the expression of CD4+ FoxP3+ T cells in spleen lymphocytes (P=0.061)， downregulate the proportion and total number of CD4+ IL-17+ T cells (P＜0.05)，and thereby increasing the Treg/Th17 ratio (P＜0.05)；the expression of Treg and Th17 in lymph node lymphocytes of CIA mice in the WJTLS group showed no obvious effect (P＞0.05). Conclusion：Wenjing Tongluo Powder can improve the inflammation score and pathological damage of joint tissue in rheumatoid arthritis models， reduce synovial tissue proliferation and infiltration of inflammatory cells. Its mechanism is related to upregulating Treg cells，inhibiting Th17 cell expression，and regulating the balance of Treg/Th17 cells.