Once pulmonary embolism occurs in lung cancer, it can mainly lead to cough, shortness of breath, chest pain, blood in sputum, and in severe cases, it can lead to dyspnea and even various symptoms such as shock, syncope and sudden death, of course, the most typical symptoms are cough, chest pain and dyspnea. Pulmonary embolism is a relatively common complication of lung cancer, which often leads to acute cough, dyspnea, hypoxemia, and even shock, syncope and sudden death in severe cases, and it is often too late for diagnosis or treatment, and the patient’s life is in danger. Therefore, patients with lung cancer should be careful whether they have pulmonary embolism or not. The main screening means is to do pulmonary CTA, which is pulmonary artery angiography to confirm the diagnosis. If a patient with lung cancer develops the above symptoms, timely CTPA examination can detect whether there is pulmonary embolism or not.