[en] Objective: The aim of the authors was to investigate the pathomorphology changes of spleen lymphocyte apoptosis after ⁶⁰Co γ-irradiation. Methods: The mice were irradiated with 6, 9, 12, 15 and 20 Gy of ⁶⁰Co γ-rays. At different times after irradiation, the mice were sacrificed and the pathological changes of spleen lymphocyte were observed by light and transmission electron microscopies. Results: Spleen lymphocyte decreased evidently and the peak of apoptosis in spleen lymphocyte was dependent on radiation dose and the time after irradiation. Conclusion: After γ-irradiation with large doses, pathological changes of spleen lymphocyte apoptosis in mice can be divided into obviously different stages. The main causes of death of spleen lymphocytes are different in different dose groups