Venous thrombosis is an abnormal clotting of blood in the veins due to a variety of causes, mostly in the deep veins of the lower extremities, and can occur in the intermuscular veins of the lower legs to the iliac veins and even the inferior vena cava. Thrombosis can sometimes be life-threatening, and the sequelae of thrombosis at a later stage can seriously affect the patient’s ability to work and quality of life, and should be actively prevented and treated. Deep vein thrombosis is a common disease in vascular surgery and can occur at any age. And its appearance is mostly seen in the lower extremities, and it has been reported that the chance of deep vein thrombosis after major surgery is as high as 10-25%. The causes of deep vein thrombosis can be caused by the combined effect of three factors: 1, venous endothelial injury can be secondary to local factors such as vascular injury, infection or other tissue damage, or can be caused by vasoactive substances. Endothelial injury can release a large amount of coagulation factors and cause vasoconstriction, while platelet and fibrin deposition can lead to thrombosis; 2. Blood stasis For example, prolonged bed rest, post major surgery, hemiplegia, reduced blood volume, local compression and other factors that cause venous blood stasis may induce deep vein thrombosis. In addition, anatomical factors are also an important cause of thrombosis. The left common iliac vein is often held by the right common iliac artery, which is the fifth lumbar vertebra, resulting in local obstruction of return flow, which leads to a higher incidence of deep vein thrombosis in the left lower extremity than in the right. 3. Hypercoagulable blood Some specific factors or diseases may cause the blood to be in a hypercoagulable state, i.e. prone to thrombotic events. For example, tumors, pregnancy, long-term estrogen use, DIC, severe infections, diabetes mellitus, kidney disease, hereditary thrombin deficiency, etc. are all prone to DVT when combined with other risk factors. Usually we think that DVT is a common disease in the West and not common in the Chinese population, but nowadays, its incidence is not low and is still increasing. There are three main types of DVT: peripheral, central and mixed. When the mixed type DVT extensively involves the deep and superficial veins of the lower limbs as well as the intermuscular plexus, the lower limbs are highly edematous, with severe pain and dark purple skin of the affected limbs, often accompanied by arterial spasm, which becomes femoral cyanosis. In the case of acute thrombosis of the deep veins of the lower extremities, the edema of the lower extremities reaches its peak within a short period of time, stimulating the arteries to spasm continuously, and the limbs become pale, which becomes white swelling of the femur. The latter two are the most serious and special types of deep vein thrombosis and require early blood flow opening, otherwise they may lead to limb necrosis. The common clinical manifestations of lower extremity DVT are sudden asymmetric swelling of the limb, which may be accompanied by local pain, hypothermia, superficial venous anger, and possible local deep pressure pain. The most commonly used test is color Doppler ultrasound. Of course, it is also necessary to combine clinical history and blood test results to make a proper determination. Venography is still considered the gold standard, but not many of them are actually used for diagnostic significance in clinical practice. Once the venous thrombus is dislodged, it may cause pulmonary embolism and cause corresponding symptoms, manifested as wheezing, hemoptysis, chest pain, and even syncope after hypoxia, which may lead to sudden death in severe cases. For deep vein thrombosis, the most important work is prevention. Once deep vein thrombosis occurs, anticoagulation therapy should be carried out actively and regularly, and some patients need to undergo emergency surgical thrombectomy. In recent years, with the development of endoluminal technology, catheter-contact thrombolysis has gradually become the treatment of choice. This method is minimally invasive, effective, and maximizes thrombus dissolution while preserving valve function and reducing long-term complications, and most patients can achieve good results with timely consultation, reasonable monitoring, and proper management. On this basis, balloon dilation and stent implantation can be performed according to the angiographic findings to determine the presence of stenosis or even occlusion. In the meantime, the chance of pulmonary infarction in the perioperative period is greatly reduced by the protection of the inferior vena cava filter. Deep vein thrombosis can be prevented and treated, and prevention is important. Once it occurs, reasonable and effective treatment and removal of risk factors are needed at an early stage. Long-term standardized anticoagulation is an effective means to reduce the risk of recurrence or reoccurrence of deep vein thrombosis.