Aim To observe the expression of calcium sensing receptor(CaSR) in atherosclerosis rat vascular endothelial cells and the relationship with apoptosis. Methods 144 Wistar rats were randomly divided into control group(n=72) and atherosclerosis groups(n=72). Early atherosclerosis models were copied by injection of vitamin D3 D360 million units/kg body weight,and then fed with high fat diet for 6 weeks. Serum triglyceride(TG) and total cholesterol(TC) were detected by automatic biochemistry analyzer. The morphological changes were observed under optical microscope. The mRNA and protein expressions of CaSR,Bcl-2,Bax and Caspase-3 were analyzed by Western blotting and RT-PCR. Apoptotic cells were measured by TUNEL staining. Results Compared with control group,the apoptosis index and the expression of CaSR,Bax and Caspase-3 were increased,Bcl-2 expression were decreased,the changes in aorta thoracica were aggravated in the atherosclerosis group. Conclusion CaSR may participate in the apoptosis of vascular endothelial cell,and then accelerate the formation of atherosclerosis.