A 8 month old infant with pulmonary artery sling and partial anomalous pulmonary venous drainage was reported. The patient was seen initially with severe stridor. Diagnosis was made by barium swallow study, echocardiography, bronchoscopy, and pulmonary arteriography. The patient was operated on through a median sternotomy; the left pulmonary artery was dissected deep between the trachea and esophagus, and then reimplanted to the side of the main pulmonary artery. Systemic heparinization and microsurgical technique were used. Simultaneous intracardiac repair was carried out by means of extracorporeal circulation. The patient improved dramatically after operation. Postoperative pulmonary arteriogram revealed a wide patent left pulmonary artery, and postoperative perfusion lung scan confirmed improved perfusion of the left lung. It is concluded that pulmonary artery sling should be treated surgically as soon as diagnosed. From the surgical point of view, the left pulmonary artery should be anastomosed to the main pulmonary artery with micro-surgical technique to avoid late occlusion of the left pulmonary artery.