Abstract: Objective: To investigate the antitumor effects of cetuximab of the epidermal growth factor receptor monoclonal antibody combined with gemcitabine on triple negative breast cancer MDA-MB-231 cells. Methods: The growth inhibitory and apoptosis of MDAMB-231 cells treated with different concentration drugs were detected by MTT and flow cytometry PI staining,respectively. The bcl-2 expression in MDA-MB-231 cells were detected by western blot. Results: The survival rate of MDA-MB-231 cells treated with 75 g / ml of cetuximab combined with 10 mol / L gemcitabine for 48 h was 48. 53%. The apoptosis rate of MDA-MB-231 cells treated with 75 g / ml of cetuximab combined with 2 mol / L of gemcitabine( 45. 7%) was significantly higher than that in these cells treated with cetuximab alone( 16. 5%)( P 0. 01). The bcl-2 expression in MDA-MB-231 cells treated with gemcitabine was downregulated,the downregulation of which was more obvious after combination with other drugs. Conclusions: The cetuximab combined with gemcitabine in the treatment of triple negative breast cancer MDA-MB-231 cells can inhibit proliferation and promote apoptosis,a combination of two drugs show additive or synergistic effect.