Objective To analyze the electrocardiogram (ECG) and troponin (cTnI) in patients with acute coronary syndrome (ACS), so as to assess their value in diagnosing the extent of vascular lesions. Methods The results of ECG, cTnI and coronary angiography (CAG) were analyzed in 37 patients with ACS. Chi-square test and a logistic regression model were used for statistical analysis. Results In patients with positive ECG or cTnI, the results of Chi-square test showed that the incidences of coronary occlusion (P=0.016, 0.003, respectively) and coronary stenosis (P=0.121, 0.013, respectively) were significantly higher than for those with negative ECG or cTnI. The results of logistic regression analysis indicated that only cTnI was significantly correlated with coronary occlusion (P=0.013) and moderate to severe coronary stenosis (P=0.021). ECG has significant consistency with cTnI (Kappa=0.617, Plt;0.001). Conclusion Both ECG and the qual itative cTnI test can reflect the extent of vascular lesions in patients with ACS.