The infant was born by cesarean section at 33 weeks of gestational age due to fetal echocardiography suggestive of transposition of the great arteries and was admitted to the intensive care unit of the cardiac center by the cardiologist immediately after birth. The clinical diagnosis: transposition of the great arteries, unclosed foramen ovale, unclosed ductus arteriosus, coronary artery staging: 1LCx, 2R. The infant was born 10 days after birth and under general anesthesia with medium and low temperature extracorporeal circulation for transposition of the great arteries, and postoperative ventilator assisted breathing for 6 days and positive inotropic drug cardiac support for 8 days. The baby was discharged after reaching a weight of 2000 g at 24 days postoperatively. After discharge, he was followed up until 3 months of age, with a milk intake of 90 ml and a weight of 5,000 g, compared to his twin birth weight of 5,500 g (birth weight of 1,780 g). Transposition of the great arteries (also called complete transposition of the great vessels) is the most common form of cyanotic congenital heart disease in the neonatal period (referred to as precordial disease). The anatomical malformation lies in the misalignment of the two great arteries (aorta and pulmonary artery) connecting the two ventricles, i.e., the aorta connects to the right ventricle and the pulmonary artery connects to the left ventricle, resulting in severe hypoxia after birth, which can lead to systemic organ failure and life-threatening if not operated on in time. The surgical procedure for this disease is to transpose the two great arteries and graft the coronary arteries at the same time. The best time to operate for transposition of the great arteries with intact ventricular septum is within 14 days after birth. In this case, the baby was a small, preterm, low birth weight (less than 2500g) twin, and the risk of surgery is extremely high because of the imperfect development of its organs. In recent years, the lowest weights reported in China for successful surgery were 2200 g and 1850 g. In this case, the weight of the baby was even lower, but the surgery was successful. Our experience is that the treatment of difficult and critical precocious heart disease requires close teamwork, including accurate fetal cardiac ultrasound diagnosis, rational perinatal management, adequate preoperative preparation, and superb surgery, anesthesia and extracorporeal circulation, as well as careful postoperative monitoring, to achieve the best timing of surgery and improve the success rate and postoperative quality of life in this patient.