Poor venous reflux in the lower extremities is mainly due to venous valve insufficiency or proximal venous obstruction in the lower extremities, and there are several common main causes. The first cause, congenital weakness of the vein wall, weakness of the superficial vein wall can cause blood to pool in the superficial veins, resulting in poor venous return. The second cause is incompetence or absence of valves. Incompetence of valves causes regurgitation of venous blood in the valves, especially in the venous sinuses, resulting in the inability of blood to return to the inferior vena cava in time, leading to poor venous reflux throughout the lower extremities. Some patients also have congenital absence of venous valves, and the degree of poor reflux is even more serious. The third cause is intravenous hypertension due to various causes of proximal venous obstruction. Such as Buga syndrome, iliac vein compression syndrome, and deep vein thrombosis sequelae, most of the intravenous hypertension is a secondary cause, which leads to poor reflux and causes a series of clinical symptoms.