Introduction: Hemodynamics of left atrial appendage (LAA) is an important factor for future risk of ischemic stroke in atrial fibrillation (AF) patients and velocity encoded cardiac magnetic resonance imaging (VENC-MRI) can evaluate blood flow volume of LAA without any invasive procedures. We aimed to evaluate the impact of radiofrequency catheter ablation (RFCA) on LAA hemodynamics via MRI evaluation. Methods and Results: Consecutive RFCA cases in a single arrhythmia center were retrospectively analyzed. A total of 3,120 AF patients who underwent first RFCA were analyzed. Among these patients 360 patients had both pre- and post-RFCA VENC-MRI evaluation. Atrial fibrillation was non-paroxysmal in 174 (48.3%) patients. Mean VENC-MRI (ml/sec) was significantly improved after RFCA with 49.75±32.97 and 71.92±34.94 for pre- and post-RFCA, respectively. Patients with non-paroxysmal AF (∆VENC-MRI = 29.71±35.30 vs. 14.42±40.94; p < 0.001) and low pre-RFCA VENC-MRI (∆VENC-MRI = 50.64±28.92 vs. 16.72±38.39; p < 0.001) had significantly higher improvement in VENC-MRI. Those who experienced late recurrence before post-RFCA MRI had significantly less improvement in LAA flow volume (∆VENC-MRI = 15.55±41.41 vs. 25.75±37.00; p = 0.016). Similar results were obtained after adjusting covariates. Conclusions: Radiofrequency catheter ablation can significantly improve hemodynamics of LAA in AF patients. The beneficial effects were most prominent in non-paroxysmal AF, those who had low pre-RFCA VENC-MRI, and those without late recurrence. Whether the improved hemodynamics of LAA after RFCA actually leads to reduced risk of ischemic stroke should be evaluated in future trials.