Aim To research the regularity of endogenous carbon monoxide and expression of carbon monoxide synthase (heme oxygenase 1) during atherosclerosis development in rabbits. Methods Reverse transcription-polymerase chain reaction(RT PCR), in situ hybridization, immunohistochemistry stain, and some biochemical index marks were performed so as to research the regularity of endogenous carbon monoxide and expression of carbon monoxide synthase (heme oxygenase 1) during atherosclerosis development. Results The positive score of heme oxygenase 1 mRNA is distributed in endothelial cell of aorta and coronary artery,the express of heme oxygenase 1 mRNA on aorta and coronary artery increase in process of time during atherosclerosis development.the positive score of heme oxygenase 1 protein is distributed in endothelial cell of aorta and coronary artery,the express of heme oxygenase 1 portein on aorta and coronary artery raise in process of time during atherosclerosis development.Through RT PCR method , the express of heme oxygenase 1 mRNA on aorta raise in process of time during atherosclerosis development was observed.The activity of heme oxygenase and the concentration of carbon monoxide increase in process of time during atherosclerosis development. Conclusion Endogenous carbon monoxide and carbon monoxide synthase may play an important role in atherosclerosis development. 还原