Objective To analyze the clinical effect through 20 adult atrial septal defect repair cases with totally thoracoscopic and summarize the experience of totally thoracoscopic cardiac surgeries.Methods From March 2014 to August 2016, 20 adult atrial septal defect cases repaired by totally thoracoscopic were enrolled in the study. Extracorporeal circulation was established by inserting artery pump tubes into the right femoral artery and vein tubes in to the right femoral vein, cold blood cardioplegia was perfused ante gradely through the aortic root in order to protect the myocardium, then atrial septal defect repair cardiac surgeries were implemented by perforating 3 holes through the right chest wall. Analyze the operation time, aortic cross clamping time, CPB time, amount of drainage, hospital stay, postoperative complications and so on.Results The operation time was 3.5~5.0 h, and the average level was (3.8 ± 0.5) h. The blocking duration of the ascending aorta ranged from 28 to 46 min, and the average level was (29.8 ± 8.2) min. The duration of extracorporeal circulation ranged from 86 to 108 min, and the average level was (80.6 ± 11.5) min. Ventilation time ranged from 5 to 8h, and the average level was (6.0 ± 0.8) h. The amount of thoracic drainage ranged from 100 to 260 ml, and the average level was (150.0 ± 35.0) ml. Hospital stay ranged from 6 to 9 days, and the average level was (6.5 ± 1.2) days. All the operations were completed successfully. There were no in-hospital death or serious post-operative complications. UCG performed 3~5 days after the operation revealed surgical results were satisfactory. Follow up to 1~28 months were available in all cases. During the period, the heart function was conifrmed asⅠ level.Conclusion Adult atrial septal defect repair surgeries with totally thoracoscope is safe and reliable and have advantages of less injury, rapid discovery, light pain, and less postoperative drainage.