Objective To evaluate the effect of angiotensin-converting enzyme inhibitor (ACEI)/angiotensin II receptor blocker (ARB) therapy on the prognosis of patients with atrial fibrillation (AF). Methods A total of 1, 991 AF patients from the AF registry were divided into two groups according to whether they were treated with ACEI/ARB at recruitment. Baseline characteristics were carefully collected and analyzed. Logistic regression was utilized to identify the predictors of ACEI/ARB therapy. The primary endpoint was all-cause mortality, while the secondary endpoints included cardiovascular mortality, stroke and major adverse events (MAEs) during the one-year follow-up period. Univariable and multivariable Cox regression were performed to identify the association between ACEI/ARB therapy and the one-year outcomes. Results In total, 759 AF patients (38.1%) were treated with ACEI/ARB. Compared with AF patients without ACEI/ARB therapy, patients treated with ACEI/ARB tended to be older and had a higher rate of permanent AF, hypertension, diabetes mellitus, heart failure (HF), left ventricular ejection fraction (LVEF) < 40%, coronary artery disease (CAD), prior myocardial infarction (MI), left ventricular hypertrophy, tobacco use and concomitant medications (all P < 0.05). Hypertension, HF, LVEF < 40%, CAD, prior MI and tobacco use were determined to be predictors of ACEI/ARB treatment. Multivariable analysis showed that ACEI/ARB therapy was associated with a significantly lower risk of one-year all-cause mortality [hazard ratio (HR) (95% CI): 0.682 (0.527-0.882), P = 0.003], cardiovascular mortality [HR (95% CI): 0.713 (0.514-0.988), P = 0.042] and MAEs [HR (95% CI): 0.698 (0.568-0.859), P = 0.001]. The association between ACEI/ARB therapy and reduced mortality was consistent in the subgroup analysis. Conclusions In patients with AF, ACEI/ARB was related to significantly reduced one-year all-cause mortality, cardiovascular mortality and MAEs despite the high burden of cardiovascular comorbidities.