Abstract：【Objective】To evaluate the value of three-dimensional transesophageal echocardiography（3D-TEE）in the applica? tion of percutaneous left atrial appendage occlusionin patients with atrial fibrillation.【Methods】7 patients with atrial fibrillation in Da? lian area（female 4，male 3，mean age 71.5 ± 3.3 years）were enrolled in the study.The maximum and minimum diameter and the max? imum depth ofleft atrial appendage were measured by 3D-TEE，and export morphology and leaf number were viewed.WATCHMAN occlude size was selectedby 3D-TEE. The process of operation was monitored by 3D-TEE. 3D-TEE was also performed in 3 months after the transcatheter closure.【Results】7 patients were performed the transcatheter closure therapy successfully. Preoperative 3DTEE showed left atrial appendage export：5 cases were oval，and 2 cases were nearly circular. The leaf number was 1.6 ± 0.8. The maximum diameter of the left atrial appendage export was（23.1 ± 1.7）mm，（19.2 ± 2.1）mm minimum diameter，maximum depth of（27.6 ± 3.3）mm. The maximum diameter had good correlation with the size of occluder（r = 0.944，P = 0.001）. 3D-TEE was used for guidance in the transcatheter therapy and succeeded. There were 1 case with little shunt after the transcatheter closure. 3 months af? ter the treatment，position and shape of the occluderswere all in good.【Conclusion】3D-TEE has the great value in the percutaneous closure of left atrial appendage.