Aim To discuss the foreboding of avL lead T wave shape changes in ECG for the blocking of the coronary left anterior descending branch middle part in acute coronary syndrome. Methods Check the coronary angiography records and the electrocardiogram of the patients treated with coronary angiography in Shengjing Hospital in Huaxiang District of China Medical University from January 2009 to July 2010 due to acute coronary syndrome by information centre, in the 194 cases the average age was 65 years old, 140 cases were male. According to avL leads T wave shape, the patients were divided into inversion group and non-inversion group to analyze the relationship of avL lead T-wave and coronary artery disease by Logistic regression analysis. Results Compared with non-avL lead T-wave inversion group, the stenosis of middle left anterior descending artery was higher in T-wave inversion stenosis group （P<0.05）. T wave inversion and middle left anterior descending artery stenosis degree were independently associated（P<0.05）. Conclusion