Necrotizing pneumonia (NP) is a rare but serious complication that occurs after foreign body retention. We report a case of severe NP in an infant caused by foreign body retention in the airway with no choking history. After a timely tracheoscopy and effective antibiotic treatment, her initial clinical symptoms were alleviated. However, she subsequently exhibited pulmonary manifestations of necrotizing pneumonia. To reduce the risk of NP from foreign body aspiration, for patients with airway obstruction and asymmetrical opacity of both lungs, timely diagnostic bronchoscopic evaluation is essential.