Abstract: Objective To evaluate the application of bronchoalveolar lavage in sub-emergency surgery for congenital heart disease infants with severe pneumonia. Methods A total of 25 congenital heart disease infants with severe pneumonia who were admitted to Xuzhou Children's Hospital, Xuzhou Medical University, from December 2016 to December 2019, were enrolled. According to the random number table method, they were randomly divided into two groups: an observation group (n=12) and a control group (n=13). The observation group received bronchopulmonary lavage after establishment of extracorporeal circulation, while the control group underwent routine surgery. Then, both groups were compared for the time of postoperative ventilator-assisted ventilation, the length of intensive care unit (ICU) stay, clinical pulmonary infection score (CPIS) and postoperative complications. Results All the patients were cured before discharge. Compared with the control group, the observation group presented decreases in the postoperative ventilator-assisted ventilation time and length of ICU stay (P<0.05), as well as the time that CPIS reduced below 6 scores, and the time that procalcitonin (PCT) and white blood cell count (WBC) return to the normal (P<0.05). Conclusions During extracorporeal circulation sub-surgery for congenital heart disease infants with severe pneumonia, bronchoalveolar lavage is conducive to lung infection control, and can ameliorate postoperative pulmonary function, reduce mechanical ventilation time and the length of ICU stay.