Lower extremity deep vein thrombosis is a common disease in vascular surgery, clinically manifested as sudden and obvious swelling of one lower extremity, and the main complication in the early stage (within two weeks) is fatal pulmonary embolism, for which anticoagulant thrombolytic therapy after implantation of inferior vena cava filter is preferred. The more aggressive and regular the early treatment, the more complete the swelling of the affected limb will be, and the lower the chance of future complications. If the disease is not treated actively and regularly in the early stage, the thrombus will not dissolve completely and gradually become old, which may leave obvious sequelae and block the lower limb deep vein for a long time and cause obstruction of reflux, clinically manifested as obvious swelling of the affected limb, darkening (pigmentation) of the skin in the boot area (distal calf and foot), and even the formation of recurrent and persistent chronic ulcers, which seriously affect the quality of life of patients. Some patients with old deep vein thrombosis of the lower extremities show occlusion of the iliac vein (located in the pelvis) and the common femoral vein (located at the root of the thigh), and this type of patients can open the occluded segment of the iliac-femoral vein through interventional treatment, which can significantly improve the venous return of the affected limb and relieve the symptoms of the affected limb. In recent years, the author has achieved significant results in the treatment of old lower limb deep vein thrombosis through intervention. The chronic ulcer of lower limb caused by lower limb deep vein thrombosis for 10 years was completely cured within a short period of time (1 month) by interventional combined with minimally invasive surgical treatment. Figure 1 Chronic ulcer of the lower leg caused by old lower limb deep vein thrombosis, which had been prolonged for 10 years. Figure 2 Puncture angiography of the femoral vein on the affected side shows a severe stenosis-occlusion of the iliac vein on the affected side, and the contralateral iliac vein is visualized through collateral circulation. Figure 3 An inferior vena cava filter was implanted intraoperatively to prevent pulmonary embolism. Figure 4 After balloon dilation and stenting, the affected iliac vein is completely opened and the contralateral iliac vein is no longer visualized. Figure 5 In order to promote ulcer wound healing, postoperative punctiform skin grafting was performed, and all of the implanted skin pieces were viable. Figure 6 Four weeks after admission, the ulcer wound of the lower leg was completely healed, and the skin removal wound was well healed.