Deep vein thrombosis of the lower extremities occurs in pregnancy, orthopedic surgery, hemiplegia and people who are bedridden for a long time. The main cause of its formation is known as Virchow’s theory, which is mainly caused by slow blood flow, blood hypercoagulation and vascular damage. It often manifests itself as sudden swelling and pain in the lower extremities, especially in the posterior calf muscles, which are particularly painful when gently squeezed. After thrombosis, because the venous blood in the lower extremities is returning to the heart, the clot, once dislodged, can run with the blood back into the pulmonary artery, causing blockage of the pulmonary artery. This condition is medically known as acute pulmonary artery embolism. If there is an embolism in the main pulmonary artery, the lung can’t get blood supply from the heart, which can cause a large area of pulmonary infarction, and in case this happens, the patient can die within minutes, which is the most dangerous complication after lower limb DVT. So for the lower limb DVT must be prevented, especially in the post-surgery, hemiplegic, long-term bedridden patients, proper lower limb activities and lower limb elevation 30 degrees lying down can help the lower limb venous blood return, thus well prevent the formation of lower limb DVT caused by slow blood flow. In addition, if the lower extremity deep vein thrombosis occurs, there is not nothing we can do, we can prevent pulmonary artery embolism through the inferior vena cava internal filter implantation, because the shape of the filter is a lantern-shaped titanium metal stent, divided into two layers, just like the sieve of rice, which can effectively block the dislodged blood clots from entering the heart, while there is basically no effect on the normal blood flow, so that the placed filter can This way, the placed filter can effectively prevent the occurrence of pulmonary embolism and save the patient’s life. The inferior vena cava filter is inserted into the inferior vena cava through a special pushing system under DSA monitoring by simply puncturing a thin needle at the base of the thigh, which is a minimally invasive procedure with minimal trauma, quick recovery and basically painless for the patient. After the filter is placed, the doctor can then proceed with thrombolysis (dissolving the clot away through drugs) or surgery with confidence and boldness. Since 2003, our vascular surgery department has been carrying out filter placement treatment for patients after acute lower limb deep vein thrombosis, and based on this, we have carried out retrievable filter placement to prevent pulmonary embolism, especially for young patients, retrievable filter placement avoids the inconvenience caused by permanent filters. It is welcomed by patients and effectively avoids the occurrence of fatal pulmonary embolism caused by dislodged thrombus.