Abstract: Objective To investigate the effects of methionine restriction treatment on the protein expression in human gastric carcinoma cell lines SGC-7901. Methods Cell apoptosis was validated by Hoechst fluorescent staining and flow cytometry test.The differences of protein expressions in SGC-7901 cells treated with methionine restriction were analyzed through the results from two-dimensional electrophoresis. Results Some apoptotic bodies were found in some gastric cancer cell lines cultured with M-H+ medium,and the proportion of apoptotic cells in M-H+ medium was significantly higher than that in M+H- medium（P<0.01）.By two-dimensional electrophpresis,16 protein spots were detected to be different. Conclusion The change of proteins expression in cells was directly reflected by two-dimensional electrophoresis.The expressions of some proteins are increased and some reduced in SGC-7901 cells after methionine restriction treatment.