There are many causes of bilateral lower extremity edema, which are generally seen in the following cases: 1. cardiogenic edema, such as edema caused by heart failure, which is generally dominated by the bilateral lower extremities; 2. nephrogenic edema, such as chronic nephritis and renal insufficiency, which is caused by tissue laxity and can also cause bilateral lower extremity edema; 3. hepatogenic edema, such as edema caused by hypoproteinemia in patients with hepatocellular carcinoma and cirrhosis; 4. 4, edema of thyroid origin, seen in patients with hypothyroidism; 5, idiopathic edema of unknown origin, which is also more common in clinical practice; 6, vascular problems in the lower extremities, such as varicose veins in the lower extremities, thrombosis in the deep veins of the lower extremities and venous valve malfunction in the lower extremities can lead to edema in the lower extremities; 7, obesity edema, seen in women due to The edema is caused by the obstruction of blood circulation. Since there are many causes of double lower limb edema, it is recommended that when double lower limb edema occurs, we should go to the hospital for detailed examination to clarify the diagnosis, find the problem early and treat it early.