Atrial septal defect accounts for 10-15% of congenital heart disease. The traditional method is to perform atrial septal defect repair under cardiac arrest in extracorporeal circulation, which is very traumatic and painful for patients. Nowadays, large cardiology hospitals mostly use – non-external circulation atrial septal defect blocking via chest wall, and minimally invasive atrial septal defect blocking is the most advanced minimally invasive cardiac surgery technique in China. Treatment method: 3 “keyholes” of about 2~3cm in length are made in the chest wall, and the atrial septal defect is closed by atrial puncture guided by cardiac ultrasound with the heart beating. Advantages: generally no blood transfusion, minimal trauma, aesthetics, quick recovery, and can be out of bed by the 2nd day after surgery. Patients recover quickly after these minimally invasive surgeries and can be discharged from the hospital in 3-5 days. The surgical scars are small and not easily detectable, and the surgical results are excellent, catering to the modern cosmetic needs. Modern minimally invasive surgery for congenital heart disease requires safe, reliable, easy to operate, less traumatic, aesthetic and less complications to facilitate its application and promotion. Therefore, it is required that: 1. the incision can be enlarged when necessary; 2. the incision should be able to be cannulated to establish CPB; 3. the sternum should not be transected as much as possible and the internal mammary artery should be protected to prevent difficulties when performing cardiac reoperation. In the clinical practice of treating atrial septal defects for a long period of time, transthoracic non-external circulation atrial septal defect occlusion can fully meet these requirements.