Prospective study in ASD (atrial septal defect) patients underwent atrial septal occluding with Amplatzer device at Department of Cardiology, Hospital No.175 from the beginning of 2008 to Jun 2013. Vent size has been checked by both of transthoracic echocardiogram (TTE) and transesophageal echocardiogram. Clinical symptoms, ECG and echocardiography characteristics, sizing balloon of patients were collected before and in procedure. Results and complications were recorded after procedure and TTE was examined 3 months later. The results show that, percutaneous atrial septal occluding therapy with Amplatzer device is a safe procedure (96.3 percent), high success rate, low complication on the basis of compliance with the principles of patient selection and technical processes. There is a clear improvement in echocardiographic parameters in patients after procedure 3 months later.