Abstract: Objective：To investigate the value of ischemia modified protein (IMA), Cystatin C (CysC) and N-terminal pro-brain natriuretic peptide (NT-proBNP) in early diagnosis of acute coronary syndrome (ACS) and its clinical significance. Methods：120 patients with ACS (the ACS group) treated in the 〖BP(〗Emergency Department and Department of Emergency or Cardiology of Henan Provincial Chest Hospital from June 2015 to June 2016 were selected, and a total of 50 healthy subjects (the healthy group) were also selected. The serum levels of IMA, CysC, and NT-proBNP were compared between the two groups, and the subgroup analysis was performed according to the results of disease diagnosis. The receiver operating characteristic curve (ROC) was used to analyze the diagnostic value of IMA, CysC, and NT-proBNP in early differential diagnosis of ACS. Results：The level of IMA in the ACS group was lower than that in the healthy group (P＜0.05). The levels of CysC and NT-proBNP in the ACS group were higher than those in the healthy group (P＜0.05). There was no significant difference in the IMA level between ST segment elevation myocardial infarction (STEMI), non ST segment elevation myocardial infarction (NSTEMI) or UA subgroup. The NTproBNP level in the STEMI group was higher than that in the NSTEMI group (P＜0.05). The scores of CysC, NT-proBNP, and Gensini in the STEMI group and the NSTEMI group were higher than those in UA group (P＜0.05). The sensitivity of IMA+CysC+NT-proBNP in diagnosing ACS was 86.29%, specificity was 92.23%, and the value of AUC was 0.912. Conclusions：IMA+CysC+NT-proBNP combined diagnosis of ACS has high clinical practical value.