Objective To summarize the clinical expedence in surgical treatment and prognosis of artrial septal defect(ASD)in adults and to know well the surgical indication of ASD in adults.Methods 32 patients over 20 years old with the left to right shunt and preoperative mean pulmonary artery pressure less than 8kPa underwent direct surgical repair for ASD under extra corporeal circulation.Results All patients survived after surgery,there was no surgical mortality in our group.32 patients were followed-up,29 of them with disappearing symptoms and 3 of them still had various symptoms.Conclusion The following condition ASD in adults who have slight to moderate clinical symptoms should be operated:cardiac enlargement eardiothoracic ratio over 50% and pneumonemia in X-ray films;right ventricular hypertrophy with a right axis deviation of incomplete right bundle branch block on the electrocardiogram;diameter of ASD over 1.5cm in ultrasonic cardiogram.