In order to explore the effects of low dose microwave on mice hematopoietic injuries induced by γ-rays irradiation, male Kunming mice were treated randomly with control, the microwave, the γ-rays irradiation and microwave combined with γ-rays irradiation respectively. The microwave group and combined group were pre-exposed to 120 μW/cm,2, microwave with 1h/d and sustained 14 days. And the γ-rays irradiation and combined group were further exposed to 5.0 Gy of ,60,Co γ-ray radiation at the 15,th, day. Animals were sacrificed at the 3, 6, 9 and 12 day after irradiation. The sternum and spleen paraffin section were produced and the pathological changes were quantitatively obtained. The results show that bone marrow is obviously injured either by γ-rays or combined radiation, which is characterized by undergoing four-phase lesions, namely apoptosis-necrosis, void, regeneration and recovery phase. Compared to γ-rays group, the pathological changes in combined group are slighter and the recovery is quicker. The spleen coefficient of combined group is significantly higher than that of the γ-rays group at the 9,th, and 12,th, day after irradiation (,p,<,0.05). The pathological changes of spleen are similar to that of bone marrow. All these injuries in the combined group are lighter than that in the γ-rays group. It has been demonstrated that pre-exposure with low dose microwave could reduce the γ-rays hematopoietic damage in this experimental conditions.