The etiology of Plastic bronchitis (PB) is unknown. The incidence of pulmonary infection associated with PB has increased year by year, but respiratory syncytial virus (RSV) as a pathogen causes PB has rarely been reported. A 2-year-old immunocompromised girl was admitted to the hospital with cough, fever for 5 days, and aggravated with shortness of breath for 1 day. With mechanical ventilation, her respiratory failure was not relieved, and subcutaneous emphysema and mediastinal pneumatosis appeared. Extracorporeal membrane oxygenation (ECMO) was administrated, but the tidal volume was low. Therefore, a bronchoscopy was performed, by which plastic secretions were found and removed. Pathology of the plastic secretions confirmed the diagnosis of type I PB. RSV was the only positive pathogen in the alveolar lavage fluid by the next-generation sequencing test. After the bronchoscopic procedure, her dyspnea improved. The patient was discharged with a high-flow nasal cannula, with a pulse oxygen saturation above 95%. Half a year after discharge, she developed sequelae of bronchitis obliterans. RSV could be an etiology of PB, especially in an immunocompromised child. In a patient with pulmonary infection, if hypoxemia is presented and unresponded to mechanical ventilation, even ECMO, PB should be considered, and bronchoscopy should be performed as soon as possible to confirm the diagnosis and to treat.