To investigate the relationship between left ventricular (LV) myocardial mechanics evaluated by three-dimensional speckle tracking echocardiography (3D-STE) and degree of coronary artery stenosis in patients with coronary artery disease (CAD). Ninety-seven suspected CAD patients without LV regional wall motion abnormality (RWMA) observed visually form traditional echocardiography were divided into four groups according to coronary artery angiography (CAG): 23 patients in slight stenosis group [stenosis rate (SR) ≤25%], 26 patients in mild stenosis group (25< SR ≤50%), 28 patients in moderate stenosis group (50< SR ≤75%), and 20 patients in severe stenosis group (SR >75%). Global longitudinal strain (GLS), circumferential strain (GCS), radial strain (GRS), area strain (AS) and three dimensional strain (3D-Strain) were obtained. The parameters from 3D-STE were compared between different groups and then the diagnostic value of global strains indicating different graded coronary artery stenosis was analyzed by the receiver operating characteristic curve. (1) There were significant difference in GLS, GCS, GRS, GAS and 3D-Strain between the severe stenosis group and any other group while all 3D-STE parameters except GCS in the moderate stenosis group were remarkably different from those respectively in mild group. (2) Receiver operator characteristic curve (ROC) analysis showed that the area under the curve of GLS, GRS, GCS, GAS, 3D-Strain were 0.899, 0.873, 0.723, 0.856 and 0.863 respectively for the identification of stenosis rate >50%, and 0.896, 0.866, 0.797, 0.909 and 0.899 respectively for the identification of severe stenosis. GAS less than −29.13% allowed a sensitivity of 95% and a specificity of 71.4%, while 3D strain less than 41.35% allowed a sensitivity of 90% and a specificity of 80.5% for evaluating serve coronary artery stenosis. The myocardial mechanics from 3D-STE in the CAD patients were characteristic. It could be expected to identify serve coronary stenosis with a good sensitivity and an acceptable specificity by using GAS or 3D-strain especially in the suspected CAD patients without RWMA on conventional echocardiography.