Objective:To investigate the association between abnormal left atrial appendage function and thrombotic events in patients with non-valvular atrial fibrillation, and the independent risk factors affecting left atrial appendage function.Methods:Patients with non-valvular atrial fibrillation, who visited the Atrial Fibrillation Center of the First Affiliated Hospital of Xinjiang Medical University from June 1, 2019 to June 1, 2021, were selected. According to left atrial appendage flow velocity (LAAFV), they were divided into normal left atrial appendage function group (297 patients with LAAFV ≥ 40 cm/s) and abnormal left atrial appendage function group (85 patients with LAAFV<40 cm/s). Baseline data and transesophageal echocardiography images were collected from all the patients. The occurrence of thrombotic events was recorded. Univariate and multivariate unconditional logistic regression analyses were conducted to investigate the correlation between abnormal left atrial appendage function and the occurrence of thrombotic events.Results:There were significant differences in gender, type of atrial fibrillation, CHA 2DS 2-VASc score, anticoagulant therapy, total cholesterol, low-density lipoprotein cholesterol, international normalized ratio (INR), left atrial diameter, proportion of patients with right atrial enlargement, left ventricular ejection fraction, inner diameter, sum of inner diameter, depth, and sum of depth of all angles of the left atrial appendage, and incidence of thrombotic events between the two groups (all P<0.05). After adjusting for confounders, multivariate unconditional logistic regression analyses showed that abnormal left atrial appendage function was closely associated with thrombotic events (β=1.168 P=0.002), and left atrial diameter ( OR=1.084, 95% CI 1.019-1.153, P=0.011) and persistent atrial fibrillation ( OR=2.323, 95% CI 1.226-4.403, P=0.010) were independent risk factors affecting left atrial appendage function. Conclusions:Abnormal left atrial appendage function is closely associated with thrombosis. The left atrial diameter and persistent atrial fibrillation were independent risk factors affecting left atrial appendage function.