There is no authoritative information on the precursors of pulmonary embolism, and the presentation of the disease lacks specificity. Common symptoms include dyspnea, chest pain, hemoptysis, cough and so on. Pulmonary embolism is a general term for clinical syndromes, and there is no authoritative clinical information on what the precursors of pulmonary embolism are, mainly because of the diversity of symptoms of the disease and the lack of specific recognition of symptoms, so pulmonary embolism in the early stage is not easy to be detected. Usually, some patients with pulmonary embolism will have the so-called “triad” of symptoms, i.e. dyspnea, chest pain and hemoptysis. Secondly, as the disease progresses, patients may experience coughing, wheezing, fainting, restlessness, panic, and a sense of impending death. Common triggers of pulmonary embolism formation are trauma, prolonged bed rest, deep phlebitis of the lower extremities, varicose veins, obesity, diabetes, elderly people, severe hemolytic anemia, and getting out of bed suddenly after surgery. Since pulmonary embolism can be life-threatening, it requires prompt diagnosis and treatment with drugs and surgery, which can improve the survival rate to some extent. However, because of the high recurrence rate, patients need to strengthen their daily life management, cooperate with doctors to actively treat the primary disease, and go to the hospital for follow-up on time.