Objective To study the ralationship of arrhythmias and heart electrical parameters changes after transcatheter closure of ventricular septal defect (VSD) .Method 50 patients had been successfully finnished the transcatheter closure of ventricular septal defect,and then we observed ralationship of arrhythmias and heart electrical parameters changes. Results (1) Compared with the situation of VSD occluder preoperative and postoperative, during follow-up there were 20 arrhythmia cases, including bundle branch block 16 cases, including the complete left bundle branch block 2 cases,complete right bundle branch block 4 cases,a transient third-degree trioventricular conduction block 1 case, most return to normal in the follow-up. 2 Intracavitary electrogram showed before and after transcatheter closure:A-V conduction parameters A-H,H-V value of (75.10 ± 14.34) ms vs (80.67±23.03) ms and (47.9±12.61) ms vs (50.07±15.23) ms,the difference was not statistically significant ( >0.05) . Conclusions (1) Some patients with new ECG changes after transcatheter closure of VSD, manifested as an increase in bundle branch block in a week, but most return to normal,the prognosis is good. (2) Intraoperative A-H,H-V extension is not related with with postoperative slow arrhythmia;(3) Arrhythmia is a common complication after VSD transcatheler closure, to strictly selecte indications,and to avoid too large diameter are the effective measures to reduce the arrhythmias after transcatheter closure of ventricular septal defect (VSD) .