Standing for a long time appeared a leg swelling cause is mainly three aspects: first, the vein thrombosis, thrombosis will lead to the human venous reflux decline, especially after standing for a long time due to the role of gravity will lead to slowing down the return of bruising, there will be an increase in the accumulation of local bruising, so there will be leg swelling. Second, the leg itself has inflammatory lesions, when standing for a long time after the local inflammatory lesions by fatigue stimulation, causing the peripheral circulation around the decreases, will also lead to the slowing of venous return swelling situation. Thirdly, abnormal lymphatic circulation, after standing for a long time lymphatic reflux obstruction, will also appear in the distal end of the tumor. After this situation, it is best to go to the hospital for ultrasound examination of the lower extremities to see if there is any abnormality in the blood vessels. If there is no abnormality, strict bed rest should be taken and the legs should be elevated to promote the slowing down of local reflux through the effect of gravity, so that the products caused by the accumulation can be metabolized effectively. In addition, we must pay attention to keep warm and not to get cold, and if there is obvious thrombosis, we usually need interventional thrombosis or thrombolysis treatment.