In this paper the effects of pprI gene from Deinococcus radiodurans transfered by electroporation in vivo on acute radiation injury of a mammalian had been investigated and clarified. After injecting the pCMV-HA plasmid into the muscle of mice exposed to γ-rays irradiation, pprI gene was transferred into the cell of mice with electroporation technology in vivo. The deaths of mice, blood cell count and the apoptotic rates of bone marrow cells, spleen cells and thymocyte cells on the 1st, 7th, 14th, 28th, and 35th day after irradiation were investigated. The results show 6 Gy γ-rays can cause acute lethal radiation injury of mice and the death rate of transfer pCMV-HA-pprI group (1/10) is obvious lower than that of radiation group(4/10). Compared with the radiation irradiated group and transfer pCMV-HA group, the leucocyte number and the erythrocyte number in peripheral blood of the mice transferred with pCMV-HA-pprI group is significantly higher on the 7th day after irradiation (,p,<,0.05) meanwhile the platelet number is obvious higher on the 7th day and the 14th day (,p,<,0.05). On the other hand, the lymphocyte ratio get right on the 35th day, the apoptotic rate of spleen cells is significantly lower on the 7th, 14th, and 28th day (,p,<,0.05), the apoptotic rate of thymocytes is significantly lower on the 1st, 7th, 14th and 35th day (,p,<,0.05), the apoptotic rate of bone marrow cells is significantly lower on the 1st, 7th, 14th and 28th day (,p,<,0.05), the apoptotic rates of thymocytes and bone marrow cells are return to normal level on the 28th day after irradiation had also been observed in the group transferred with pCMV-HA-pprI. The result indicates that the pprI gene of Deinococcus radiodurans transfered by electroporation in vivo can prevent and cure the acute radiation injure for animals apparently.