Abstract: Objective: To explore the ultrasound indicators of predicting left atrial appendage thrombosis(LAAT) or severe spontaneous echo contrast(SSEC) in patients with non-valvular atrial fibrillation(NVAF). Methods: The transthoracic echocardiography(TTE) and transesophageal echocardiography(TEE) in 144 NVAF patients were detected.The left atrial global longitudinal strain(LAGLS),left atrial area change fraction(LAFAC),and left atrial emptying fraction(LAEF) were measured.The patients were divided into the positive group and negative group by esophageal scan for thrombus or severe spontaneous imaging in the left atrium.The value of left atrial mechanical function parameters measured by chest in predicting left atrial appendage thrombus or severe autography were investigated. Results: The mechanical function of left atrial and left atrial appendage was highly consistent,and the LAGLS was an independent predictor of LAAT or SSEC(OR=0.781,95%CI:0.682-0.893,P<0.01). Conclusions: LAGLS has independent predictive value for LAAT or SSEC in NVAF patients,and can avoid unnecessary TEE operation.