Objective To observe serum sCD40L, MMP9 levels and their relevance with different types of coronary heart disease(CHD). Methods The present study was involved in 90 patients with CHD, including acute myocardial infarction(AMI) 30 case, unstable angina pectoris(UAP) 31 case, stable angina pectoris (SAP) 29 case and another 25 normal controls.The serum MMP9 and sCD40L levels were detected with enzyme-linked immunosorbent assay. Results The levels of MMP9, sCD40L in AMI and UAP group were significantly higher than those in SAP group[(69.48±4.76)ng/mL, (66.61±5.30)ng/mL, (30.44±7.66)ng/mL, t=1.425, 0.075, all P 0.05), and also there were no ststitically signiticant differeces in the serum MMP9, sCD40L levels between SAP group with control group (all P>0.05). MMP9 level in AMI and UAP group was positively related with sCD40L (r=0.96, P<0.01 and r=0.97, P<0.01). Conclusion The serum sCD40L and MMP9 levels of acute coronary syndrome(ACS) increase significantly, and can be used as an important index to assess the severity of CAD and predict the instability of plaque in CAD patients. Key words: Acute coronary syndrome; Matrix metalloproteinases; sCD40L