Lower extremity deep vein thrombosis is a common type of venous thrombosis, accounting for 95% of venous occlusive lesions. Untimely treatment can cause varicose veins in the lower extremities and even ulcer formation, which will not heal for a long time. Some patients can develop pulmonary embolism and life-threatening. There are medical, surgical and interventional treatments for it. Interventional treatment has the characteristics of rapid and efficient, and reduces bleeding, etc., and has become the preferred treatment method. The main technical means are 1. catheter thrombolysis: it has the distinctive feature of contact thrombolysis, which makes the thrombolytic drugs work to the maximum. 2. intravenous cannula cis- and countercurrent thrombolysis: it is to insert the catheter into the thrombus to perfuse the thrombolytic drugs. After the thrombus is partially dissolved, the catheter is pushed forward and the thrombolysis is continued until the thrombus is completely dissolved. 3. Mechanical extraction and ablation of thrombus: For those who do not have obvious effect of thrombolysis after the above treatment lasts for 24 hours or those who have thrombus formation for more than one week, local thrombus fragmentation and aspiration can be performed first. The access is from the same side of the lesion, and a special thrombus aspiration catheter is used for deep thrombus aspiration under the guidance of a guidewire.4. Balloon dilation and stent placement: It is suitable for residual stenosis (chronic thrombosis) and stenosis with external pressure (tumor, COCKET syndrome) and occlusion after thrombolysis. Balloon dilation is the simplest and most practical and can be a good adjunct to catheter thrombolysis. If there is no significant effect after balloon dilation, stenting may be an option.