Abstract: The prevention of restenosis by radiation exists a lot of mecranisms, including smooth muscle cells (SMCs) division cycles arrests, inhibition of SMCs proliferation, SMCs apoptosis,inhibition of macrophage/monocyte and cytokines. Apoptosis is a major style of cell death induced by endovascular radiation. The inhibition of SMCs proliferation induced by radiation is a main mechanism for prevention of restenosis.