Background The increasingly improved Cardiopulmonary bypass (CPB) has improved the surgical outcomes of cardiac surgery progressively. But CPB-induced lung injury after operation still remains a serious complication that could lead to life-threatening problems. Objective To discuss and summarize research progress of lung injury and lung protection after CPB. Content Inflammation, ischemia-reperfusion injury, pulmonary vascular endothelial cell injury are supposed to participate in the mechanism of lung injury. Kinds of biotechnologies and drugs can be used to reduce the lung injury caused by CPB. Trend It may reduce the postoperative mortality, increase the amount of patients who are able to undergo CPB, so as to provide the patients with more reasonable and effective treatment strategy.