Abstract: Objective To investigate the relationship between inflammatory factors and the coronary artery dilation, and the clinical significance of their changes. Methods The cases performed coronary angiography in our hospital last year was collected, and they were divided into three groups , the first one included 11 patients whose angiography were coronary artery dilation, the second group included 35 cases whose results were atherosclerosis, and the third was normal angiography which included 24 cases. sES, MMP9 and TIMP1 were measured by ELISA method, and the results are compared. Results Patients with coronary artery dilation were found to have significantly higher in comparison with atherosclerosis group and normal group(153.7±152.7ng/L，90.1±54.2ng/L，76.5±37.2ng/L, respectively)(P value=0.039)，there were also statistic significance of MMP9 among three groups(2184±1723ng/L， 949± 827ng/L，1274± 1394ng/L）（P＝0.016）, but there were no statistic significant difference of TIMP-1 among three groups(8106±1218ng/L，8203±834ng/L，8433±867ng/L）（P>0.05）. Conclusion sES and MMP-9 are associated with coronary artery dilation , they maybe attribute to the coronary artery dilation, and they might play important roles in the coronary artery pathogenesis.