Objective To study the effect of Bitongkang Pills on TNF-α of collagen-induced arthritis (CIA) rats’ blood serum, explore its mechanism of therapeutic action. Methods The model of type II collagen with complete Freund’s adjuvant-induced rat CIA was established. 60 Wistar rat models were randomly divided into six groups, Bitongkang Pill low, medium and high dose groups [0.3, 3, 30 g/(kg·d)], costumes, Wang bi instant herbal medicine group 3 g/(kg·d) , methotrexate tablets group 1.2 mg/(kg·w) , the drugs of above groups were dissolved in 2 ml of saline, the rats were fed with the pills one time per day, intragastrically administered for 4 weeks continuously. The model group was fed with 2 ml saline each rat. After 8 weeks, the rats were sacrificed, underwent enzyme-linked immunosorbent assay (ELISA) to detect the CIA rat serum TNF-alpha concentration, and to observe each rat’s TNF-alpha concentration levels changes. Results The serum TNF-alpha levels in Bitongkang pills medium dose group (1190.84± 177.02), high-dose group (844.20±142.79), MTX tablets group (1149.40±182.17), Wangbi granules group (1215.83±102.07) were significantly lower than the model group (1724.67±247.26) (P=0.017, 0.000, 0.008, 0.036). The serum TNF-alpha levels in Bitongkang Pills high dose group were significantly lower than those in the Bitongkang Pills medium dose group, the MTX tablets group, and Wangbi granules group (P=0.006,0.018,0.009). Conclusions Bitongkang Pills can effectively reduce the CIA serum TNF-alpha expression, have the action of inhibiting CIA rat synovitis.