Objective To confirm the changes of pulmonary artery pressure, neo pulmonary artery stenosis and reoperation in children with unilateral absence of pulmonary artery (UAPA) undergoing pulmonary artery reconstruction. Methods The clinical data of the infants with UAPA undergoing pulmonary artery reconstruction in our hospital from February 19, 2019 to April 15, 2021 were analyzed. Changes in pulmonary artery pressure, neo pulmonary artery stenosis and reoperation were followed up. Results Finally 5 patients were collected, including 4 males and 1 female. The operation age ranged from 13 days to 2.7 years. Cardiac contrast-enhanced CT scans were performed in all children, and 2 patients underwent pulmonary vein wedge angiography to confirm the diagnosis and preoperative evaluation. Preoperative transthoracic echocardiography and intraoperative direct pulmonary arterial pressure measurement indicated that all 5 children had pulmonary hypertension, with a mean pulmonary arterial pressure of 31.3±16.0 mm Hg. Pulmonary arterial pressure decreased immediately after pulmonary artery reconstruction to 16.8±4.2 mm Hg. The mean follow-up time was 18.9±4.7 months. All 5 patients survived during the follow-up period, and 1 patient had neo pulmonary artery stenosis or even occlusion and was re-operated. Conclusion Pulmonary artery reconstruction can effectively alleviate the pulmonary hypertension in children with UAPA. The patency of the neo pulmonary artery should be closely followed up after surgery, and re-pulmonary angioplasty should be performed if necessary.