Abstract: OBJECTIVE To explore the efficacy and safe dose of Compound Xiatianwu tablets in treating collagen-induced arthritis(CIA) of mice. METHODS CIA mice were randomly divided into 6 groups: model group, normal group, positive (Tripterygium wilfordii 15 mg·kg^-1) group, Compound Xiatianwu tablets low, medium, high dose (288, 864, 1 728 mg·kg^-1) groups, with 10 mice in each group. After 21 d of treatment, the general condition and joint pathology were compared wtih each group, and the safe concentration of Compound Xiatianwu tablets and its effect on proliferation of TNF-α induced fibroblast-like synoviocyte(FLS) were explored. RESULTS Compared with model group, paw swelling of mice in treatment groups was all reduced, and arthritis index of mice in Compound Xiatianwu tablets medium, high dose groups was significantly decreased(P<0.05 or P<0.01). Pathologically, Compound Xiatianwu tablets could reduce inflammatory cells infiltration, decrease the positive expression of TNF-α and inhibit the formation of osteoclasts, and Compound Xiatianwu tablets medium, high dose groups had better effects than positive group. The safe concentration of Compound Xiatianwu tablets was ≤ 200 mg·mL^-1. Compared with model group, Compound Xiatianwu tablets high dose group had a good inhibitory effect on proliferation of FLS and there were statistically significant differences(P<0.05). CONCLUSION Compound Xiatianwu tablets can improve the general conditions of CIA mice, reduce the arthritis index, decrease the positive expression of TNF-α, inhibite osteoclast formation and FLS proliferation.