Abstract: Objective To discuss the diagnosis, treatment, and outcomes of pediatric tachyarrhythmia. Methods Clinical data of 107 pediatric inpatients with tachyarrhythmia from January 2011 to December 2014 were retrospectively analyzed. According to 24 hours holter, all patients were divided into two groups, incessant group whose supraventricular tachyrhythmia were more than 50% of heart rate, and intermittent group whose ventricular tachycardia were more than 10%. The clinical features were compared between two groups. Results In a total of 107 patients (64 male and 43 female), there were 31 cases in incessant group with the median age of 7 months which included 13 cases of paroxysmal supraventricular tachycardia (PSVT), 13 cases of atrial tachycardia (AT), 2 cases of chaotic atrial tachycardia (CAT), 1 case of atrial fibrillation (Af), 1 case of junctional ectopic tachycardia (JET), and 1 case of ventricular tachycardia (VT). Among them, 21 cases (67.7%) were progressed to tachycardiainduced cardiomyopathy. There were 76 cases in intermittent group with the median age of 6 years which included 55 cases of PSVT, 4 case of AT, 2 cases of CAT, 5 cases of atrial flutter (AF) (2 cases combined with Af), one case of Af, 3 cases of JET, and 6 cases of VT. 14 cases received monotherapy and 17 cases received combination drug therapy in incessant group. Meanwhile, 61 cases received monotherapy and 11 cases received combination drug therapy in intermittent group. In two groups, because the symptoms of tachyarrhythmias could not be controlled effectively, 17 cases had to treat by transesophageal atrial pacing, 3 cases treated by electrical cardioversion, 2 cases treated by cardiac temporary pacing, and 30 cases treated by radiofrequency ablation. In 6 months of follow-up, one case of VT relapsed, 2 cases of AF and one case of JET controlled ventricular rate in incessant group, while 7 cases of PSVT and one cases of VT relapsed, one cases of AF controlled ventricular rate, and 2 cases of PSVT and VT abandoned therapy and died respectively in intermittent group. The sinus rhythms were recovered in remaining cases. There were statistical differences in age, proportion of PSVT and other rapid arrhythmia, proportion of serum level of cTnI ≥ 0.30 ng/ml, proportion of serum level of NT-proBNP≥ 250 pg/ml, and proportion of monotherapy or combination drug therapy between two groups (P < 0.05). Conclusions It was difficult to treat intermittent rapid arrhythmia, which required combination drug therapy and was prone to develop into tachycardia-induced cardiomyopathy.