Objective:To investigate the inhibitory effect of vitamin E succinate(VES) on experimental breast cancer in nude mice. Methods:MCF7 human breast cancer cells were inoculated subcutaneously in nude mice. VES was administrated at a dosage of 150mg/kg body weight for 5 weeks. Then, the size of the tumor was measured and cell cycle and cell surface Fas/FasL were detected by flow cytometry. Fas/FasL expression in tumor tissue was detected with immunohistochemistry, and apoptosis index was detected by TUNEL method. Results:VES showed obviously inhibitory effect on the growth of graft breast cancer tumor in vivo. VES treatment blocked tumor cells in G0/G1 phase. Fas/FasL expression was upregulated accompanied with a rise of apoptotic index in tumor tissue. Conclusions:VES had potent inhibitory effect on MCF7 breast cancer graft in nude mice. The mechanism involved may be related to the upregulation of Fas/FasL expression and promotion of apoptosis of tumor cells.