Aim To explore the correlation between P-wave dispersion （PWD） & maximum P-wave duration （Pmax） and left ventricular diastolic function. Methods the paper measures PWD & Pmax of 100 coronary artery disease patients with 12-lead ECG synchronization,who are grouped into greater than 40ms and less than 40ms according to PWD,and grouped into greater than 110ms and less than 110ms according to Pmax.Indices such as severity of coronary stenosis,E/A ratio,DT,LAD,LVEDD,LVEF,paroxysmal atrial fibrillation etc.are compared among groups as well.