Background To evaluate the value of transthoracic echocardiographic (TTE) in transcatheter closure of ventricular septal defects (VSD) in Children.Methods A total of 855 patients aged 3.0-14.0 years (average 6.8 years) with VSD were occluded, including 828patients with membranous or perimembranous VSD, 9 patients with muscular VSD and 18 patients with intracristal VSD.TTE was performed before catheterization to examine the VSD and the rims, to evaluate the occluder device, and to evaluate the efficacy of the device occlusion on parasternal long axis of left ventricle, short axis of aorta and five chamber views.