Aim To investigate the level of matrix metalloproteinase-3 of peripheral blood from acute coronary syndrome patients and to analyize the relationship among matrix metalloproteinase-3,myocardium enzymes,troponins,blood-fat,and severity of coronary artery disease.Methods To contrast matrix metalloproteinase-3 of peripheral blood from 77 acute coronary syndrome patients of our hospital and normal controls,and to analyze relationship among matrix metalloproteinase-3 of peripheral blood,myocardium enzymes,troponins,blood-fat,and severity of coronary artery disease.Serum level of matrix metalloproteinase-3 was measured by enzyme linked immunosorbent assay.Results Compared with stable angina pectoris group and control group,the level of matrix metalloproteinase-3 in acute myocardial infarction group had statistically significant difference(P<0.01).Compared with stable angina pectoris group and control group,statistical significance of difference was seen in unstable angina pectoris group(P<0.01).There is no significant difference between acute myocardial infarction and unstable angina pectoris group,as well as stable angina pectoris and control group.Matrix metalloproeinase-3 and troponin I,creatine kinase,MB isoenzymes of creatine kinase had positive correlation,There were no correlation between matrix metalloproteinase-3,triglyeride,low density lipoprotein cholesterol.Matrix metalloproteinase-3 level and coronary artery radiography pathological change severity were performed by Pearson correlation: there were no correlation(r=0.293;P=0.053).There were significant difference of matrix metalloproteinase-3 in 10 patients with acute myocardial infarction before and after percutem coronary artery interventional therapy(P<0.01).Conclusion The level of matrix metalloproteinase-3 of peripheral blood in patients with acute coronary syndrome was increased.The level of matrix metalloproteinase-3 and coronary artery radiography severity had no correlation.Matrix metalloproteinase-3 and troponin I,creatine kinase,MB isoenzymes of creatine kinase had positive correlation in patients with acute myocardial infarction.