Pulmonary embolism is an acute and serious disease in the cardiovascular and respiratory fields. It is a clinical disease caused by endogenous or exogenous emboli blocking the pulmonary arteries and causing obstruction of pulmonary circulation. Due to the rapid change of the disease and atypical symptoms, it is often not easy to detect, repeated visits to the clinic without relieving the symptoms, and even patients have sudden syncope and sudden death due to acute attacks of pulmonary embolism. This is very common in reality, and many surgical patients die after getting out of bed with sudden syncope after surgery, and one of the reasons is the occurrence of pulmonary embolism. Studies show that pulmonary embolism and deep vein thrombosis are diagnosed in millions of patients worldwide each year, and in the West pulmonary embolism is listed as one of the three common cardiovascular diseases. The number of deaths due to pulmonary embolism in the United States reaches 296,400 cases per year. Approximately 60% of these patients are underdiagnosed, and only 7% of them are diagnosed and treated promptly and correctly. It can be seen that pulmonary embolism is a group of diseases with low diagnosis rate and high mortality rate, which is now getting more and more attention.