If you have lower extremity DVT, you must first choose a vascular surgeon in a regular hospital. Ultrasound or deep venography of the deep veins of the lower limbs and CT of the iliac veins should be done, and if the ultrasound reveals that the deep veins of the lower limbs have been completely recanalized, CT of the iliac veins should be done to find out the patency of the iliac veins. If the iliac veins are also excluded from occlusion and stenosis, and the patient has varicose veins and ulcers in the calves, the superficial veins of the lower limbs and the traffic branches can be dissected. If only the iliac vein is occluded and the deep veins of the lower extremity are well recanalized, then an interventional opening of the iliac vein can be performed. If ultrasound of the deep veins of the lower extremity or CT of the iliac veins suggests that the deep veins are still obstructed, conservative treatment is first considered. Conservative treatment methods include: 1, compression therapy; 2, drug therapy. Compression therapy is more effective than drug therapy. If the degree of femoral vein recanalization is good, while the iliac vein is narrow and the clinical symptoms are obvious, interventional therapy can be considered. With the progress of interventional technology and materials, the interventional procedure to unblock the iliac vein has been further applied in Europe and America in the last 5 years. 5-year patency rate has been significantly improved. Vascular surgery has also accumulated a lot of clinical experience in the interventional treatment of DVT sequelae and achieved good results. Generally, interventional surgery can be considered in the following cases: 1, high degree of recanalization of veins below the femoral vein; 2, severe stenosis or occlusion of iliac vein segments; 3, swelling and nutritional changes in the lower extremity calves (darkening of the skin, ulcers, etc.). The advantage of interventional surgery is that the venous blood flow is restored and the result is quick. However, the cost is high and the patency rate needs to be improved.