Objective The objectives of this study are to investigate the clinical characteristics and improve the diagnosis of pediatric patients with congenital unilateral agenesis or absence of pulmonal artery. Methods Cases of pediatric patients with congenital unilateral agenesis or absence of a pulmonal arterywho had been diagnosed at our hospital from 2008 to 2018 were analyzed. Results In all, five patients (3 male; age range, 0.58-13 years) with congenital unilateral agenesis or absence of pulmonal artery were diagnosed and treated in our institution.The most common clinical presentation are recurrent pulmonary infections, hemoptysis and pulmonary artery hypertension. The chest X-ray was indicative in the regular clinical examinations though it was of no value in the diagnosis. Echocardiography could demonstrate associated intracardiac defects and pulmonary artery hypertension. The catheterization and chest computed tomography scan could show distinctly the conditions of pulmonary arteries. Conclusion The common clinical manifestation of pediatric patients with congenital unilateral agenesis or absence of pulmonal artery arerecurrent pulmonary infections, pulmonary hypertension and hemoptysis. The chest X-ray and echocardiography indicate diagnosis, contrast enhanced chest computed tomography or angiography could confirm diagnosis.