Abstract: Objective 　To investigate changes of cell cycle, apoptosis and protein expression in esophageal carcinoma cells after 60 Coγ2rays irradiation, it is the basis as combing target t reatment and radiotherapy for esophageal cancer. Methods 　Using flow cytomet ry ( FCM) to check the percentage of different phase cells and apoptosis at 1, 2, 12, 24, 48 h af ter irradiation (0, 1, 2, 5, 10, 15 Gy) . Expression of MDC1 and 53BP1 were detected by Western blot af ter irradiation. Results 　The percentage of G0 / G1, G2 / M and S phase of TE213 cells was changed dependence on doses increasing of irradiation. At 12 h af ter irradiation with 1 Gy and 2 Gy, arrest of G2 / M stage was gradually increased and reached the peak at 24 h af ter irra2 diation with 5, 10, 15 Gy ( P < 0. 05) . Apoptotic index of TE213 cell was obviously elevated at 12 h, 24 h and 48 h af ter irradiation with 15 Gy ( P < 0. 01) . However, expression of MDC1 and 53BP1 proteins in TE213 cells were no significant changes at 48 h af ter irradiation with 5, 10, 15 Gy ( P > 0. 05), compared with the cont rol group . Conclusion 　G2 / M arrest and apoptosis of TE213 cells were remarkable increas2 ing af ter different doses irradiation. Meanwhile, No changes of expression of MDC1 and 53BP1 proteins in TE213 cells were investigated af ter irradiation.