Recently, our cardiothoracic surgery department successfully performed direct cardiac surgery under extracorporeal circulation on a 26-month-old male child who weighed only 10 kg. This is another case of cardiac surgery for low weight children carried out by the cardiothoracic surgery department, and the child has been discharged from the hospital. The child surnamed Chen from Ninghai County, Zhejiang Province, was found to have “congenital heart disease – ventricular septal defect” after birth, and was often hospitalized in the area due to recurrent pneumonia since birth. After visiting several large hospitals, surgical treatment was recommended, but the child was told that he was small in age and light in weight, so surgery and postoperative care were difficult and risky. He came to our cardiothoracic surgery department, and after admission, his heart ultrasound indicated that he had a 1cm giant septal defect and a significantly enlarged left ventricle with an unclosed atrial septum foramen ovale. On June 11, Dr. Zhao Guofang, Dr. Yang Minglei and Dr. Du Xuekui successfully performed ventricular septal defect repair and foramen ovale closure in the egg-sized heart of the child with the close cooperation of Hu Xukai and Wu Guorong from the Department of Anesthesiology, Dong Caijun and Hu Yiqi from the extracorporeal circulation and the operating room. After the operation, under the careful care of ICU and cardiothoracic surgery staff, the child recovered successfully and was discharged from the hospital. It is a challenge for surgeons, anesthesiologists, extracorporeal circulation perfusionists, ICU and ward nurses to perform extracorporeal cardiac surgery on low weight infants.