Objective To evaluate efficacy and safety of transcatheter closure of secundum atrial septal defects(ASD) by domestic made septal occluder.Methods Two hundred and seventy-eight patients with secundum ASD were selected as our subjects who all underwent transcatheter closure by domestic septal occluder guided by transthoracic echocardiography in Fujian Provincial Hospital form Nov.2002 to Jun.2012.Transthoracic echocardiography was applied to evaluate pulmonary artery pressure,right ventricular end diastolic diameter and complications at time points of 48-72 hours,1-12 months after closure.Patients with other combined malformations during follow-up periods were performed intervention therapy.Results Among 278 patients,the diameters of ASD were ranged from 5.5 to 41.0 mm and the average was (21.5 ± 6.7)mm.Two hundred and seventy-eight occluders were implanted,including 4 small-waist occluders,6 fenestrated occluders and 12 double occluders.The occluder diameters were ranged from 6.0 to 48.0 mm and the average was (26.3 ± 7.2) mm.The success rate regarding of technique was 95.7％ (266/278) and the procedure success rate was 95.3％ (265/278).The pulmonary artery systolic pressure after closure decreased from (37.7 ±8.6) to (31.5 ±5.8) mmHg through cardiac catheterization (t =4.403,P ＜0.05).The incidence of total severe complications was 2.5％ (7/278),including 1 case of occluder detachment,2 cases of oecluder dislodgement,1 case of device embolization to right ventricular inlet,1 case of occluder thrombus formation,1 case of small pericardial effusion,1 case of death.Other complication occurrence rate was 4.0％ (11/278),including 5 cases with transient inferior ST segment elevation,1 case with transient III degree atrioventricular block,4 cases with paroxysmal atrial fibrillation,1case with the right femoral arteriovenous fistula.Patients with small to moderate residual shunts were 22,10,7 respectively at immediate post-operation,48-72 hours and 1-12 months.pulmonary artery pressure and right ventricular end diastolic diameter were ((41.5 ± 16.3),(36.4± 11.2),(29.5 ±9.3) mmHg respectively; (37.3 ± 8.7),(34.1 ±6.8),(30.3 ±7.2) mm respectively) at time points of before operation,48-72 hours,1-12 months after closure.Pulmonary artery systolic pressure decreased significantly after operation,and right ventricular end diastolic diameter were further markedly reduced after closure during the follow-up periods (F =30.387,28.223,P ＜ 0.001).Furthermore,all patients with succeed surgery showed no new arrhythmia,thromboembolism,hemolysis,atrioventricular valve dysfunction,occluder dislodgement and embolization.Conclusion Transcatheter closure of secundum ASD using domestic septal occluder is proved effective,safe and reliable with a low incidence of severe complications in the short term,suggesting it can be a preferred treatment on the most selected secundum atrial septal defect patients with occluded indications.