Abstract: Objective To study the value of electrocardiogram（ECG） in diagnosis of coronary heart disease and in assessment of coronary artery lesions. Methods Coronary arteriography and ECG of 778 patients with coronary heart disease admitted to the cardiology center in January-June 2008 were analyzed.The severity of coronary artery lesions was assessed using the Gensini scoring system. Results A total of 567（72.9%） of the 778 patients with coronary heart disease had positive coronary arteriography.Three hundred and ninety-nine（70.4%） of the 590 patients with abnormal ECG and 168 of the 188 patients with normal ECG were diagnosed as coronary heart disease.The diagnostic sensitivity and specificity of ECG were 70.4% and 9.5%,respectively.The positive rate of ECG was higher in patients with severe coronary heart disease than in those with moderate and mild coronary heart disease（81.6% vs 76.5% and 57.0%,P=0.000）. Conclusion Abnormal ECG can help to assess the moderate or severe lesions of coronary artery in patients with coronary heart disease.Coronary arteriography should be performed for those with risk factors for coronary heart disease and abnormal ECG.