Abstract: Objective To investigate the relationship between epicardial adipose tissue (EAT) and thromboembolism event in patient with atrial fibrillation (AF). Methods One hundred and fifty-five patients with non-valvular AF who were planning to undergo cathete ablation in our hospital from January 2013 to May 2015 were chosen. The total EAT volume (EAT-total), atrial EAT volume (EAT LA) were measured by CT. All patients were divided into two groups (thromboembolism group and control group) based on whethe they had ischemic stroke, transient ischemic attack, or the history of thromboembolism related to AF, then the parameters between the two groups were compared and the relationship between epicardial adipose tissue and thromboembolism event in patients with atrial fibrillation were evaluated. Results Of the 155 patients, 22 (14%) had a history of thromboembolism and they were enrolled in thromboembolism group with average age of (62.50±10.42) years and 7 females (28.6%). The other 133 patients were in contro group with average age of (54.45±10.81) years and 38 females (31.8%). Compared with control group, the EAT-total and EAT LA in thromboembolism group increased significantly (123.49±31.25) cm³vs (100.71±35.04) cm³, P=0.005; (34.58±6.32) cm vs (26.89±9.65) cm³, P＜ 0.001. After controlling for age, vascular disease, hypertension, diabetes and LA diameter, multivariable linear regression analysis showed that EAT-total and EAT-LA were independently associated with thromboembolism in patients with AF. Conclusion These results suggest that EAT may be an independent risk factor of thromboembolism in patients with AF