Post deep vein thrombosis syndrome (PTS) is the most important late complication of acute deep vein thrombosis of the lower extremities, with a reported incidence of about 7 to 82%. The main manifestations are leg pain, edema and heaviness, easy fatigue or hyperpigmentation, and severe manifestations account for 7% to 23%; while ulcers occur in 4% to 6%, and it is estimated that about 400,000 to 500,000 patients in the United States have venous ulcers caused by late thrombosis, and some patients will lose their labor force as a result. Post DVT syndrome is mainly caused by regurgitation and persistent venous obstruction due to valvular insufficiency. It has been shown that about 1/3 to 2/3 of patients with DVT have regurgitation due to valve disruption on ultrasound 1 year after the disease. The following factors have been found to contribute to the post-embolism syndrome: the proportion of early obstructed veins that recanalize, the degree of regurgitation, the location of regurgitation and obstruction, and the recurrence of thrombosis. After acute lower extremity deep vein thrombosis, the incidence of post-deep vein thrombosis syndrome increases as the duration of disease increases. In contrast, the post-deep vein thrombosis syndrome due to proximal obstruction (large veins) is three times higher than that due to distal embolism. Compression therapy is the main method of preventing and treating PTS. Although some studies have shown that wearing high compression compression stockings for 2 years can reduce the incidence of post DVT syndrome by 50%. However, I personally believe that if there are no contraindications and if the patient can afford it, it is recommended that the patient wear compression stockings for a longer period of time or even for life to prevent the development of post DVT syndrome, which is especially important in patients with proximal obstruction.