Pulmonary embolism may lead to pulmonary circulation and respiratory dysfunction, with high morbidity and mortality rates, and is a serious disease that requires prompt treatment and even resuscitation. Pulmonary embolism is a clinical syndrome caused by various emboli embolizing the pulmonary artery and its branches, which can be classified into pulmonary thromboembolism, fat embolism, amniotic fluid embolism, air embolism and so on according to different emboli. Pulmonary thromboembolism is mainly caused by deep vein thrombus obstructing the pulmonary artery, which will cause pulmonary hypertension as well as left and right cardiac insufficiency; the lung tissue in the obstructed area will have gas exchange obstruction, leading to respiratory insufficiency, hypoxemia, and so on. Fat embolism usually occurs after long bone surgery, and air embolism occurs after gynecological surgery and cardiac surgery. Amniotic fluid embolism occurs most often during labor and delivery and can cause anaphylactoid reaction, disseminated intravascular coagulation, pulmonary hypertension, etc. It leads to respiratory failure and shock, and may be fatal within minutes, which is an aggressive condition with a high mortality rate. Pulmonary embolism is a serious condition and early recognition and treatment may be life-saving.