The unilateral absence of pulmonary artery (UAPA) is a rare congenital cardiovascular malformation, which is asymptomatic and easy to be ignored in early stage. A large number of complications may occur in the later stage. Therefore, early diagnosis and treatment is of great significance. The imaging data of 49 patients with UAPA discovered and confirmed clinically by the echocardiography in our hospital are analyzed. The results show that left pulmonary artery absence is more common (55%) and most of them are associated with other cardiovascular malformations (92%). Atrial septal defect and patent foramen ovale were most common in 56%. In which the absence of isolated pulmonary artery was 8% (4/49), and the absence of right pulmonary artery was 75% (3/4). Especially in the patients with tetralogy of Fallot, 77% (5/9) of them miss the diagnosis of UAPA. This suggests that doctors and sonographers should pay attention to the development of pulmonary artery bifurcation and left and right branches in multi-section, and strengthen the scanning of short axis section of high large artery.