Interventional treatment of atrial septal defect has become a routine treatment method, and about 70% of patients with atrial septal defect can be treated with satisfactory results. In view of the size of atrial septal defect blockers in China, the largest diameter of atrial septal defect blocked in our hospital is 36 mm, and for huge atrial septal defects of about 35 mm, the effect of interventional treatment is exact and satisfactory. A typical case is attached. The patient, female, 50 years old, was admitted to the hospital with “a heart murmur for more than 20 years and chest tightness after activity for more than 3 years”. Combining the medical history, symptoms, signs and auxiliary examinations (electrocardiogram, chest X-ray, echocardiogram), she was diagnosed with “congenital heart disease, atrial septal defect and pulmonary hypertension”. After thorough preparation, interventional closure of the atrial septal defect was performed under local anesthesia. The echocardiogram showed that the atrial septal defect was about 36 mm in diameter and the surrounding stump margin was weak. The operation was successful and he was discharged with a 5-day hospital stay. He was hospitalized for 5 days. He was reviewed several times after the operation and the result was good. He is now able to perform normal physical work. The main procedure of the operation is shown in Figure 1 and Figure 2. Key points of the operation: 1. Although the atrial septal defect of the patient was huge, there were still edges around it, and a larger diameter blocker should be chosen because the edge of the residual edge was weak; 2. The blocker was easily dislodged into the right atrium during the blocking process of this patient, and the right superior pulmonary vein release method was applied, and the blocking was successful; 3. The operation was completed in our one-stop composite operating room, and the contingency plan was made to make it foolproof; 4. Postoperative follow-up showed that the shape of the atrial septal defect was satisfactory and there were no complications such as residual shunt. Figure 1 After blocking, push-pull test was performed Figure 2 Release of blocker