In the past decade, there is a great progress in the treatment of atrial fibrillation (AF) by transcatheter ablation. The catheter-based procedures have developed from Maze-like linear lesion, focal lesion to segmental electrical isolation of pulmonary veins and circumferential ablation under guidance of anatomical mapping, ablation energy developed from radiofrequency to multiple energy such as radiofrequency, ultrasound and cryoablation; and success rate has risen to 90% from around 30% in the past.~1 Catheter ablation has been widely accepted as a treatment of AF and tends to substitute pharmacological therapy and become first-line treatment gradually. It must point out that, however, catheter ablation of AF is not perfect and there are many issues desiderating resolution. In the past decade, there is a great progress in the treatment of atrial fibrillation (AF) by transcatheter ablation. The catheter-based procedures have developed from Maze-like linear lesion, focal lesion to segmental electrical isolation of pulmonary veins and circumferential ablation under guidance of anatomical mapping, ablation energy developed from radiofrequency to multiple energy such as radiofrequency, ultrasound and cryoablation; and success rate has risen to 90% from around 30% in the past. ~ 1 Catheter ablation has been widely accepted as a treatment of AF and tends to substitute pharmacological therapy and become first-line treatment gradually. It must point out that, however, catheter ablation of AF is not perfect and there are many issues desiderating resolution.