Objective To clarify the value of transesophageal echocardiography (TEE) for evaluating left atrial appendage (LAA) hemodynamics and predicting LAA thrombus in patients with nonvalvular atrial fibrillation. Methods 138 atrial fibrillation patients and 30 controls were enrolled in our study. The atrial fibrillation patients were classified into two groups: LAA thrombus group (N=15) and LAA non-thrombus group (N=123). At the 2D-TEE mid-esophageal views, LAA flow spectra and tissue velocity imaging (TVI) of 0, 45, 90 and 135 degree were obtained respectively. LAA ejection fraction (LAAEF), LAA maximal volume (LAAV_max), LAA minimal volume (LAAV_min), LAA filling peak flow velocity (LAA-FV), LAA emptying peak flow velocity (LAA-EV), LAA average filling flow velocity (LAA-AFV), LAA average emptying flow velocity (LAA-AEV), LAA walls systolic and diastolic peak velocity were measured. Results Compared to the control group, LAA-EV, LAA-FV of atrial fibrillation group were lower and LAAV_max were higher (P<0.01). But there were no significant differences between thrombus group and non-thrombus group. LAA-AEV, LAA-AFV, LAAEF gradually reduced in control group, non-thrombus group and thrombus group. The cut-off value of LAA-AEV and LAA-AFV were 33.0cm/s and 27.5cm/s respectively (specificity were 0.80 and 0.73, respectively, sensitivity were 0.87 and 0.97, respectively) for predicting LAA thrombus. Conclusions TEE can effectively reflect LAA hemodynamics and function. The LAA systolic and diastolic function of nonvalvular atrial fibrillation patients are lower, and even worse in those with thrombus. LAA-AEV and LAA-AFV are good parameters which can provide more references for predicting LAA thrombus in nonvalvular atrial fibrillation patients．