Aim To detect the early diagnosis value of thrombus precursor protein (TpP) in acute coronary artery syndrome. Methods 51 cases of coronary artery disease were divided into two subgroups of unstable pectoris angina and acute myocardial infarction. Thrombus precursor protein and creatine kinase (CK and CKMB )concentration were determined in all patients. Resluts Thrombus precursor protein concentration of the acute myocardial infarction subgroup increased significantly than the unstable pectoris angina subgroup(9.9±3.9 mg/L vs 2.6±1.8 mg/L,p<0.01);also,CK and CKMB concentration of the acute myocardial infarction subgroup increased significantly than the unstable pectoris angina subgroup (595±432 u/L vs 137±40 u/L,p<0.05; 101±74 u/L vs 10±7 u/L,p<0.01,respectively). Conclusion Thrombus precursor protein concentration of the acute myocardial infarction subgroup increases significantly,but not in the unstable pectoris angina subgroup. Thrombus precursor protein has differentiated and early diagnostic value for the acute myocardial infarction in patients with acute coronary artery syndrome.