Alveolar surface active substance is a complex synthesized and secreted by alveolar type II epithelial cells, which can effectively prevent alveolar hyperinflation during inspiration and alveolar collapse during expiration, and can effectively maintain the relative stability of alveolar volume and increase lung compliance. Alveolar surface-active substances allow excess fluid in the alveoli to cross the air-blood barrier and be transferred to the interstitial space of the lungs, which can maintain fluid balance in the alveoli and prevent the formation of pulmonary edema. A variety of lung diseases, such as respiratory distress syndrome and interstitial pneumonia, can occur as a result of alveolar surface active substance deficiency. It is generally the main cause of morbidity and mortality in newborns, older children and adults, and is mostly treated clinically with alveolar surface active substance replacement therapy, as well as mechanical ventilation.