In order to investigate the death mode of hematopoictic cells in mouse bone marrow irradiated by neutron and γ-rays, 350 BALB/C mice, which were whole body irradiated with varies doses of neutron and γ-rays, were sacrificed at 6 and 12hours, 1, 2, 3, 4, 5, 7, 10, 14, 21 and 28days after irradiation respectively. By means of light microscope, electron microscope, flow cytometry, in situ terminal end labeling and DAN gel electrophoresis, the apoptosis and necrosis of hematopoietic cells were investigated. The results showed that the amount of hematopoietic cells occurring apoptosis and necrosis were obviously increased after neutron irradiation and the necrosis was main death mode in irradiation dose of 5.5Gy. Meanwhile, γ-irradiation mainly induced apoptosis of hematopoietic cells and the apoptosis was correlated to the irradiation dose. It means that there were different death modes of hematopoietic cells in mouse bone marrow irradiated by neutron and γ-rays. Neutron mainly induced necrosis of the hematopoietic cells though apoptosis also occurred in irradiation dose of 5.5Gy, while γ-rays mainly induced the apoptosis.