We retrospectively analyzed 1125 cases of atrial septal defect repair with minimally invasive thoracic incision during 3 years to discuss the experience of surgery under extracorporeal circulation with minimally invasive incision. Methods From March 2005 to March 2008, a total of 1125 cases of minimally invasive thoracic incision atrial septal defect repair were performed, including 985 cases with a small right axillary incision and 140 cases with a “7” type incision in the lower sternum, 655 cases in men and 470 cases in women, aged 1DD25 years. The small right axillary incision was made in the left lateral position, with an oblique incision from the posterior axillary line to the anterior axillary line, 8DD12 cm in length, and entered the chest through the fourth intercostal space. The lower part of the sternum was incised in a “7” shape up to the second intercostal space and down to the glabella, and the right half of the sternum was transected from the glabella up to the second intercostal space to the right, and the sternum was propped open, the pericardium was incised and suspended, and extracorporeal circulation was established. Results No surgical death in the whole group, 2 cases of postoperative second open chest hemostasis, 1 case of atrial pericardial bleeding, 1 case of intercostal vascular bleeding. 20DD350ml (average 85ml), no incision infection, all healed and discharged. Conclusion 1. Minimally invasive incisions in the chest for simple cardiac surgery are safe and feasible; 2. Minimally invasive incisions have the advantages of small, hidden and cosmetic incisions; 3. Small incisional drainage and fast recovery, but high operating techniques are required, and intraoperative attention should be paid to prevent dangerous complications caused by side injuries; 4. Small axillary incisions are suitable for young children, while small sternal incisions are more suitable for young adults.