Diabetes mellitus is prone to a variety of chronic complications, especially in elderly patients. The following conditions need to be considered in elderly diabetic patients with swollen feet: i. Combined diabetic nephropathy, when there is positive urine protein or renal insufficiency, there can be hypoproteinemia appearing as swelling of both lower extremities. Second, heart disease or even heart failure, can appear swelling of both lower limbs. Third, combined lower extremity vasculopathy, when diabetic patients combined with bilateral lower extremity venous reflux disorders or arterial plaque, can appear swollen feet. In elderly diabetic patients, swelling of both lower extremities can also occur when combined with hypothyroidism and cirrhosis of the liver. Fifth, certain drugs, such as insulin, thiazolidinediones and calcium antagonists, can cause sodium and water retention, resulting in swollen feet in elderly diabetic patients. Therefore, elderly diabetic patients with swollen feet need to go to the hospital for further examination to identify the cause.