Abstract: The treatment of vessel restenosis by endovascular radiation is being taken into account. However, the mechanism for prevention of restenosis is not clear. Restenosis is a complex process that comprises endothelial cells and others. It appears, fundamentally, to be a wound-healing process. The injury of vascular endothelium is initial influence on the development ofrestenosis. The proliferation and apoptosis of endothelial cells will effect and intervene in the course of restenosis. Ionizing radiation will influence survival, apoptosis, proliferation, phenotype and function for endothelial cells. It will contribute the prevention of restenosis by means of the study of the effect of ionizing radiation on vascular endothelial cells.