Objective：To summarize our initial experience on threedimensional electroanatomic mapping with CartoMerge, so as to provide evidence for guiding catheter ablation of atrial fibrillation (AF). Methods: Fifteen patients with paroxysmal/persistent AF (13 paroxysmal and 2 persistent), who were to receive catheter ablation, were analyzed by CARTOMERGE, which combines computed tomography (CT) angiography, picture merging, guiding ablation, etc. Results: There were 103±13 mapping points before ablation, with 66±15 in the left ablation circle and 58±20 in the right. The distance between points and surface was (1.8±0.2) mm in the merged images. Operation time was (305±45) min and the Xray exposure time was (52±18) min. Isolation of pulmonary veins potential was achieved in all patients and there was no complication during the operation. Conclusion: Threedimensional CT images is very close to the the real anatomy of left atrium and pulmonary veins. Cartomerge technique can overcome some shortcomings of Carto electroanatomic mapping pictures, which can improve the successful rate of operation and reduce complications.