BACKGROUND:: In recent years, studies have shown the effects of tumor necrosis factor-α (TNF-α) on fibroblasts at different organizations in a tissue-specific and dose-dependent manner. OBJECTIVE:: To investigate the biologic effects of TNF-α and its signal transduction pathway-specific kinase inhibitors on mouse embryonic fibroblasts (NIH3T3). METHODS:: NIH3T3 cells were cultured in vitro, and then the cells were assigned into 3 groups. Cells in the control group were cultured in DMEM high-glucose medium with 2% serum; those in the TNF-α group were cultured in 100 μg/L TNF-α medium; those in the TNF-α+Anti-TNFRSF1B group were firstly cultured in medium with 50 μg/L Anti-TNFRSF1B for 1 hour, and then placed in the medium with 100 μg/L TNF-α. RT-PCR and Western blot methods were used to evaluate mRNA and protein expressions of type I collagen and matrix metalloproteinase 3 (MMP3) in each group. RESULTS AND CONCLUSION:: In this experiment, NIH3T3 cells cultured with a certain concentration of TNF-α, the specificity kinase signal of transduction pathway presented with phosphorylation or protein activation, and the signal pathway was activated, which promoted MMP3 activation, and significantly reduced the expression of type I collagen. The effect of TNF-α was certainly inhibited, but not completely eliminated after adding its signal transduction pathway inhibitor Anti-TNFRSF1B. This further proves the role of TNF-α on NIH3T3 activation.