Some people will disagree when they say that pulmonary embolism is a common disease. If an autopsy study of people who died suddenly found that nearly 1/3 of them had pulmonary embolism, then you must be surprised. What is pulmonary embolism, those who are prone to get it, how to prevent it and how to treat it. Pulmonary embolism refers to endogenous and exogenous emboli blocking the pulmonary arteries or branches with pulmonary circulation and respiratory dysfunction as the main clinical and pathophysiological features. Most of them originate from venous thrombosis of the lower extremities. People who are prone to pulmonary embolism: long-term bed rest such as post-operative bed rest, post-traumatic bed rest, elderly bed rest, long-term oral contraceptives, pregnancy or childbirth, thrombophlebitis, varicose veins, atrial fibrillation in heart failure, bacterial and fungal endocarditis, severe trauma, long bone fracture, venous cannulation, obesity, high blood viscosity, high blood lipids, high blood sugar and smoking. Since most pulmonary embolisms originate from lower extremity venous thrombosis, it is important to prevent lower extremity venous thrombosis. Those with the above risk factors and sudden onset of symptoms and signs of hypoxia such as chest pain, exertional dyspnea, palpitation, cough, or even hypotension and cardiac arrest need to be alerted to the possibility of pulmonary embolism. Diagnosis: X-ray chest X-ray, electrocardiogram and echocardiogram are preferred in community hospitals and have diagnostic value. Pulmonary CTA is preferred in larger hospitals, followed by cardiac ultrasound and radionuclide lung perfusion scan. Positive blood D-dimer (> 500 μg/ L) may also be indicated. In case of bacterial fungal or foreign body emboli, or acute thrombo-pulmonary embolism with life-threatening thrombosis, pulmonary artery dissection and embolization under extracorporeal circulation should be treated with an aggressive attitude. Besides, anticoagulation and thrombolytic therapy are fundamental to the treatment. If there is thrombosis in the veins of lower extremities, an inferior vena cava filter should be implanted. However, thrombolytic therapy is not ideal for those with more than 1 week of disease. After entering the chronic phase and the symptoms stabilize, long-term anticoagulation, usually warfarin, is used. Most pulmonary artery and lower extremity thrombi disappear completely in 3 months-12 months on warfarin. Anticoagulation is recommended for life. In addition to anticoagulation, treatment targeting cardiopulmonary function should also be available. Of course, it is correct to visit the hospital and listen to the doctor’s advice.