objective To study the effects of large ionizing radiation exposure on murine lung tissues . Methods The mice was exposed to 60Co γ ray at 16 Gy. The pulmonary injury was observed after hematoxylin-eosin staining and the expression levels of TGFβ1 and ICAM1 were detected with immunohistochemistry . Results The murine lung showed evident injury three days after large ionizing radiation exposure and the expression levels of TGF-β1 and ICAM1 increased significantly. Conclusion The endothelial cell injury and the intravascular material leakage would be the early important events，and early detection of ICAM1 might be helpful to predict the severity of acute radioactive lung injury.