The common causes of swollen feet after walking for a long time include the following: First, the injury or strain of the lower limbs caused by prolonged walking, resulting in swelling, congestion, edema, inflammatory reaction of the lower limb tissues, increased tissue interstitial pressure restricting venous return, local bruising and symptoms of swollen feet. Second, it can be seen in the lower limb venous diseases, including phlebitis, varicose veins, after more activities, due to the local tension increase caused by venous reflux restriction, the symptoms of swollen feet. Third, it can be seen in patients with cardiac insufficiency or renal insufficiency, who have poor water and sodium metabolism, and after more activities, it will lead to water and sodium retention in the lower limbs and swelling. Fourth, due to the tight dressing of the lower limbs, the shoes are more squeezed or the pants are tighter, and the non-elastic tension tends to restrict the venous reflux and swelling occurs, compared to the elastic stockings, which have no elasticity and contraction ability and will not promote the venous blood reflux in the lower limbs, which will also produce the symptoms of swollen feet.