Aim To observe the changes of soluble intercellular adhesion molecule-1(sICAM-1) and pregnancy associated plasma protein-A(PAPP-A) levels and to explore its clinical value combining with coronary angiography(CAG) results in patients with acute coronary syndrome(ACS). Methods The levels of serum sICAM-1 and PAPP-A were measured with enzyme linked immunosorbent assay(ELISA) in 46 patients with ACS,22 with stable angina pectoris(SAP) and 20 coronary angiography negative as controls.The results of the three groups and different numbers of diseased coronary vessels in coronary heart disease(CHD) group were analyzed. Results sICAM-1 in ACS group was significantly higher than that in SAP group(p<0.05) and control group(p<0.01),PAPP-A in ACS group was significantly higher than that in SAP group and control group(p<0.01).The sICAM-1 and PAPP-A concentrations were increased in the 1-vessel-disease group,the 2-vessel disease group,and the 3-vessel-disease group.In patients with acute myocardial infarction(AMI) and unstable angina pectoris(UAP),there were obvious correlations between sICAM-1 and PAPP-A(r=0.737,and r=0.758,p<0.001). Conclusions The levels of sICAM-1 and PAPP-A increased in ACS patients,which may reflect the instability of atherosclerotic plaques.