The clinical features and risk factors of pericardial effusion complicating radiofrequency catheter ablation (RFCA) in a large sample of Chinese Han patients with tachyarrhythmias have rarely been reported. We summarized the clinical characteristics and analyzed the risk factors of pericardial effusion complicating RFCA in 1,756 Chinese Han patients with tachyarrhythmias. There were 27 patients with pericardial effusion after RFCA. Of these patients, 10 developed cardiac tamponade; the symptoms of 9 patients were relieved after pericardiocentesis and drainage, while 1 patient was discharged after emergency surgical repair. The rate of pericardial effusion in patients with atrial fibrillation was significantly higher than in those with other tachyarrhythmias (P < 0.001). The proportion of female patients, hypertension, diabetes mellitus, coronary heart disease, age, left atrial size, and length of hospitalization in the pericardial effusion group was significantly increased compared with the non-pericardial effusion group (P < 0.01). Multivariate logistic regression analysis showed that female sex and atrial fibrillation were independent risk factors of complications by pericardial effusion after RFCA in patients with tachyarrhythmias. Age and left atrial size in female patients and those with atrial fibrillation were significantly higher than in male patients and patients without atrial fibrillation. Pericardial effusion complicating RFCA is not rare in patients with tachyarrhythmias, and it tends to develop into cardiac tamponade. Emergency pericardiocentesis and drainage are the most effective therapy. Female sex and atrial fibrillation may be independent risk factors of pericardial effusion after RFCA in patients with tachyarrhythmias.