Patients with tetralogy of Fallot tend to have deviations in pulmonary artery development compared to normal, and often repair procedures are not always completed even in the presence of two pulmonary arteries. In this patient, the left pulmonary artery was absent, the left side of the own pulmonary artery could not be found as well as the large aorta to pulmonary artery collateral artery, the pediatric patient was severely hypoxic with an oxygen saturation of 60%, and the pediatric patient was 2 years old and stunted. Pulmonary artery development indicators: McGoon ratio less than 0.9 and pulmonary artery index 170 mm2/m2. Due to the markedly small McGoon, it is documented that McGoon needs to be greater than 1.2 to safely complete a complete repair. Therefore, a two-pronged approach was taken to prepare for the surgery and to preserve the ventricular septal defect if the right ventricular pressure was too high after complete repair. After complete repair, the child’s right ventricular pressure/left ventricular pressure was about 0.3, and the result was very satisfactory. The child was successfully de-extracted after surgery and discharged from the hospital. Thus, in patients with tetralogy of Fallot, complete repair can be accomplished even if only one pulmonary artery is present, as long as the other pulmonary artery is developing normally.