When the temperature is hot and cold, especially when the seasons change, it often causes the attack of vascular diseases such as heart, brain and lower limbs, and serious ones such as cerebral infarction, heart attack and cerebral hemorrhage can be life-threatening. When the temperature changes, the blood vessels throughout the body will then contract and expand to adjust to the weather changes, but when the temperature changes abruptly, the body often can not fully and quickly adjust, or poor vascular regulation itself, can not adapt to external temperature changes, it may cause the onset of vascular disease. When the temperature changes suddenly and the limbs suddenly appear swollen, painful, cold, pale, etc., we may have to consider the onset of lower limb vascular diseases, such as deep vein thrombosis, vasculitis, etc. In the case of deep vein thrombosis, the affected limb may become seriously swollen within minutes or hours, and the circumference may exceed the opposite limb by more than 10 cm, and the skin color may be dark red or blue, accompanied by pain and inability to walk. ultrasound may reveal deep vein thrombosis in the affected limb, or slow blood flow, which often requires emergency minimally invasive catheter to dissolve the thrombus and restore blood flow. If the condition is delayed for more than a week, the thrombus may be difficult to dissolve completely and the limb will be left with different degrees of swelling sequelae. If symptoms such as pain, chills, pallor, and numbness occur in the limb, they may be caused by arterial ischemia, which is often complicated by acute thrombosis following arterial embolism in the limb or its own atherosclerosis. Patients will feel severe pain and purple color in the distal foot of the affected limb in a few hours, which will progress to the lower leg or even the thigh in 1~2 days and cause partial necrosis. Therefore, it is necessary to perform minimally invasive catheter thrombolysis or surgical removal of embolus under local anesthesia to relieve the symptoms, and then further treatment is needed depending on the condition. Therefore, such symptoms must be seen in time, not overnight, otherwise the condition will be delayed and lead to amputation. Such a tragic cost is too much, and it is also very regrettable. It was just a small problem, but because of the delay in treatment and became a big problem, causing amputation, life-threatening, is really undesirable. Therefore, in case of sudden temperature changes, seasonal changes, the above-mentioned limb swelling, pain, chills, etc., must be beware of possible vascular lesions, must immediately seek medical attention to avoid delayed diagnosis and treatment, resulting in tragedy.