Aim To observe the expression of carnitine palmitoyltransferase-Ⅰ(CPT-Ⅰ) gene in vascular smooth muscle tissue during atherosclerosis at 8th,16th,24th week after high-cholesterol diet to rabbit to determine whether atherogenesis is associated with the changes in the gene expression of vascular smooth muscle tissue energy metabolism. Methods 36 rabbits were randomly and equally assigned to control group and high-cholesterol diet group.The gene expression of CPT-Ⅰ were detected in vascular smooth muscle tissue of aorta thoracalis by semi-quantitative reverse transcription polymerase chain reaction(RT-PCR) at the end of 8th,16th,and 24th week. Results 16 and 24 weeks after high-cholesterol diet,the atherosclerosis formed and expression of CPT-Ⅰ mRNA was reduced.Compared with that of 16th week,CPT-Ⅰ mRNA was reduced at the end of 24 th week. Conclusion During atherosclerosis of rabbit,the expression of CPT-Ⅰ mRNA was downregulated in vascular smooth muscle tissue.