Venous thrombosis in the lower limbs of the elderly is mostly located in the deep veins, and according to the site of thrombosis, it can be divided into central type, peripheral type and mixed type, with different symptoms, including localized pain, swelling and pressure in the lower limbs. 1. Central type: i.e. iliac vein-femoral vein thrombosis, patients are more likely to have an acute onset of disease, with obvious swelling of one side of the lower limb, pain and tenderness in the iliac fossa and femoral triangle of the affected side, with the left side more than the right side. 2. Peripheral type: i.e. femoral vein or deep calf vein thrombosis, when the thrombus is confined to the femoral vein, the swelling and pain in the thigh is obvious, but the swelling in the calf is not serious; when the thrombus is confined to the deep calf vein, the patient will have severe pain in the calf, which will be aggravated by walking, and the swelling in the calf is obvious and accompanied by pressure pain. 3. Mixed type: deep vein thrombosis of the whole lower limb, mainly manifested as obvious swelling of the whole lower limb, pain spreading to the femoral triangle, popliteal fossa, calf, accompanied by accelerated pulse rate and elevated skin temperature. If all types of lower limb venous thrombosis are not treated in time, further development of the condition may result in ischemia of the lower limbs, blisters on the dorsal skin of the lower limbs and feet, blue-purple color of the skin, or even disappearance of the dorsal arterial pulsation of the feet, and in severe cases, it may result in venous gangrene of the lower limbs; dislodgment of the thrombus may also result in pulmonary embolism, which is typically characterized by respiratory distress, chest pain, and hemoptysis. When the above symptoms occur in the elderly and deep vein thrombosis of the lower limbs is suspected, it is recommended to go to the hospital as soon as possible, so that the diagnosis can be clarified in time and the treatment can be given accordingly, and no delay can be made to avoid delaying the condition.