Abstract: The cavotricuspid isthmus is the slow conduction region in the reentrant loop of typical atrial flutter. To reach bi-directional conduction block, linear ablation of this anatomical structure has been recognized as the first-line procedure for typical atrial flutter. It is known to us that atrial fibrillation is closely related to typical atrial flutter: on the one hand, they often coexist in the same patient; on the other hand, typical atrial flutter is usually inducible in electrophysiological examination procedure in patients who are suffering atrial fibrillation. Therefore, physicians usually supplement cavotricuspid isthmus ablation to atrial fibrillation ablation procedure in order to obtain better long-term prognosis. Nevertheless, recent studies have cast doubt on the effectiveness of this linear ablation procedure. In this article, taking the relationship of these two kind of ‘Af’ as a starting point, we review the therapeutic effect of cavotricuspid isthmus linear ablation in the radiofrequency ablation procedure of atrial fibrillation.