Varicose veins of the lower extremities are common and frequent, and many patients refuse surgery because they feel no significant discomfort or because they are afraid of surgical treatment. The causes of varicose veins in the lower extremities are related to the weakness of the venous vessels, the venous valves (one-way valve structures in the venous vessels) and the persistent pressure on the veins of the lower extremities, as well as genetic factors. When the intra-abdominal pressure rises, such as prolonged standing, heavy labor, pregnancy, etc., it causes pressure shock in the venous column of the lower extremities, resulting in sinuous and tortuous veins. It is usually more obvious in the calf than the thigh. Varicose veins of lower limbs can cause ulcers and eczema on the lower legs, causing “old rotten legs” that do not heal easily, and varicose veins can also rupture and cause bleeding, and some patients can develop thrombophlebitis. Thrombophlebitis caused by varicose veins in the lower extremities is associated with slow blood flow in varicose veins, damage to the vascular wall, stagnation of blood, coupled with local skin malnutrition and weakened barrier, which can easily lead to bacterial invasion, or local trauma that causes inflammatory reactions in varicose veins. Ultrasonography may reveal that the lumen of the vein is filled with thrombus, and local skin is seen as red, swollen, leg painful, and hard masses can be palpated. Thrombophlebitis is not only painful and immobile, but in some cases it can be dangerous and life-threatening. Superficial vein thrombosis is not as easy to dislodge as deep vein thrombosis leading to pulmonary embolism, but it is still a risk. Thrombophlebitis can lead to pulmonary embolism in the deep veins due to the continued spread of the thrombus, or it can lead to pulmonary embolism in the pulmonary arteries due to the free dislodgement of the superficial vein thrombus! This is a case of a female patient who developed thrombophlebitis after prolonged varicose veins. Ultrasonography suggests that the lumen of the saphenous vein is filled with thrombus and no blood flow is seen! Patients with thrombophlebitis caused by varicose veins in the lower extremities are treated aggressively surgically after the inflammation subsides with medication to remove the varicose veins and avoid the recurrence of inflammation to form new thrombi! Varicose veins should not be kept for a long time, massage and other methods not only can not cure varicose veins, but also may lead to the formation of thrombosis, serious cases of pulmonary embolism will be life-threatening!