Pulmonary artery sling (PAS) and tracheal agenesis (TA) are both very rare diseases. Most of PAS are associated with tracheal bronchial malformations. However, PAS associated with TA have not yet been reported so far. Here, we report one case of PSA associated with TA diagnosed prenatally in our hospital. Due to the extremely low incidence of two diseases, physicians do not have sufficient understanding of these disease, prenatal ultrasound examination found that these kinds of diseases are very challenging and confusable. Prenatal ultrasound and MRI examination of pulmonary artery branches, trachea and esophagus will provide useful information. Improving the accuracy of prenatal fetal diagnosis is helpful for perinatal management and counseling.