Objective To observe the influence of interferon-γ(IFN-γ)and tumor necrosis factor-α(TNF-α)treated mesenchymal stem cells (MSCs) on the chemotherapy resistance of colon cancer cells(CRCs) and to discuss the related mechanism. Methods The supernatants of MSCs treated with IFN-γ and TNF-α were collected and used, together with chemotherapy drug cisplatin and 5-fluorouracil, to treat HCT116 and HT29 CRCs. Then the cellular morphology was observed under microscope, and the cell proliferation and apoptosis were examined by MTT and PI/Annexin Ⅴ-FITC assay. Furthermore, the mRNA levels of Bax and Bcl-2 were detected by RT-PCR. Results The CRCs treated with the supernatant of MSCs exposed to inflammatory factors, compared to CRCs treated with the supernatant of MSCs not exposed to inflammatory factors, had a slighter morphology changes, a significantly higher proliferation rate (P<0.05), and a significantly lower apoptosis rate following chemotherapy(P<0.05). Moreover, Bcl-2 mRNA level was higher and Bax mRNA level was lower in CRCs treated with the supernatant of MSCs exposed to inflammatory factors. Conclusion MSCs stimulated with inflammation factors IFN-γ and TNF-α can promote the chemotherapy resistance of human CRCs.