Acute pulmonary embolism, is a relatively rare clinical condition that is acutely fatal to the pulmonary arteries. Once a large thromboembolism, which occurs in the pulmonary artery, occurs, it can cause respiratory distress and a rapid drop in blood oxygen, resulting in sudden death of the patient. With pulmonary artery embolism, the most important source of thrombus is lower extremity deep vein thrombosis. Generally, deep vein thrombosis in the lower extremity is called the acute phase within the first two weeks. In the acute phase, the thrombus is unstable and easily dislodged. At this time, if the patient does not find clear thrombosis, the thrombus is easily dislodged during strenuous activities. Therefore, it is recommended that the patient be absolutely bedridden with the affected limb elevated and braked during the first two weeks of thrombosis. If there is a definite floating thrombus, or if there is a high risk of causing pulmonary embolism, an attempt can be made to apply inferior vena cava filter placement. Intercept the dislodged thrombus in the lower extremity to avoid causing a lethal pulmonary embolism.