Abstract: Objective To investigate the role of transesophageal echocardiography(TEE) in evaluating the left atrial appendage(LAA) function in monitoring recurrence of atrial fibrillation(AF) in patients after radiofrequency catheter ablation(RFCA). Methods A total of 84 patients in the First Affiliated Hospital of University of Science and Technology of China diagnosed with AF and undergoing RFCA for the first time were retrospectively collected from June 2016 to October 2019. After follow-up,patients were divided into the relapse group(n=19) and non-relapse group(n=65) accordingly. The clinical data of patients were collected, and TEE was used to measure relevant parameters of LAA function. In addition, the various indexes of patients between the relapse group and non-relapse group were followed-up and compared, aiming to identify risk factors. Results The diameter of left atrial antero-Posterior, the diameter and depth of the LAA in the relapse group were greater than those in the non-relapse group(all P<0.01), while the area change rate, emptying rate and filling rate were smaller in the relapse group than those in the non-relapse group(all P<0.01).The area change rate is positively related to reciprocal time(r=0.685,P=0.001), emptying rate(r=0.562,P=0.012),filling rate(r=0.627,P=0.004) and is negatively related to BNP(r=-0.558,P=0.013),depth of the LAA(r=-0.496,P=0.031).In addition, the area change rate predicted the AUC of relapse after RFCA is 0.933(0.875-0.991).The area change rate was an independent predictive factor for relapse after RFCA, and area change rate<40.95% as the cutoff value could generate the optimal predictive performance of relapse after RFCA. Conclusion Evaluation of LAA functions via TEE is of predictive value for relapse after RFCA. Moreover, the decreased area change rate is an independent predictive factor for relapse after RFCA.