The arteries of the lower extremities are the blood supply vessels of the body, while the veins of the lower extremities are the blood return vessels of the body. Therefore, lower extremity artery thrombosis can be manifested as lower extremity ischemia. When the lower extremity ischemia, the human body can appear cold skin, numbness and pain. When the veins are the blood returning vessels of human body, when the veins form thrombosis, it will lead to poor blood return to the lower extremities, and when the blood return to the lower extremities is poor, it will show as swelling and bruising of the lower extremities. The main difference between arterial thrombosis and venous thrombosis is that when arterial thrombosis of the lower extremities is found, the human body will show pale, cold and numb skin, while when venous thrombosis of the lower extremities appears, the human body will show swelling and bruising of the lower extremities, the symptoms are completely different and the treatment is also different. When lower extremity arterial thrombosis is detected, it is a vascular surgical emergency, which requires emergency surgical treatment for thrombolysis or thrombus removal. When lower extremity venous thrombosis is detected, the onset is generally considered to be milder and treatment is mostly conservative, with elevation of the affected limb followed by mild anticoagulation.