Objective：To investigate the relationship between arterial stiffness index（ASI） and the severity degree of coronary atherosclerosis. Methods：A total of 396 patients underwent coronary angiograph and the measurement of ASI using CardioVision MS-2000 arterial stiffness detector and then they were divided into three groups：group Ⅰ（ASI 0-70，186 patients）， group Ⅱ（ASI 71-140，108 patients） and group Ⅲ（ASI>140，102 patients）. The severity degree of coronary heart disease was evaluated by the numbers of involved coronary arteries. Results：There were significant differences in age， history of high blood pressure， diabetes history， systolic blood pressure， and the severity degree of coronary heart disease among three groups. The mean number of involved coronary arteries was highest in group Ⅲ， followely by group Ⅱ and group Ⅰ（P < 0.05）. There was a positive correlation between age， systolic blood pressure， high pressure history， diabetes history， lipoprotein（a）， uric acid， ASI and the number of involved coronary arteries showed by single factor correlation analysis methods. However， there was a negative correlation between high-density lipoprotein cholesterols（HDL-C） and the number of involved coronary arteries（P < 0.05）. ASI， HDL-C and lipoprotein（a） were independent risk factors of coronary heart disease showed by multiple factor logistic regression analysis method. Conclusion：ASI may be a good index reflecting arterial elasticity and can provide valuable information of the severity degree of involved coronary arteries.