Weakness of legs after hemodialysis may be caused by renal anemia, low blood pressure, low blood potassium and calcium and phosphorus metabolism disorder. 1. Renal anemia: patients with renal failure may suffer from renal anemia due to decreased secretion of erythropoietin by renal tissues, which may lead to insufficient supply of blood and oxygen to the limbs, inducing weakness of legs. 2. Low blood pressure: In the course of dialysis treatment, the blood pressure may drop due to excessive dehydration, decrease in plasma osmotic pressure and decrease in effective blood volume, leading to insufficient cerebral blood supply, which may induce dizziness and weakness of limbs and other symptoms. 3. Low blood potassium: low concentration of potassium ions in dialysis fluid may cause hypokalemia, resulting in decreased participation of potassium ions in the blood in neuromuscular function, causing symptoms of weakness of legs. 4. Calcium and phosphorus metabolism disorder: hemodialysis patients usually have low blood calcium and high blood phosphorus, which may easily induce hypocalcemia, leading to calcium deficiency in muscle tissues and causing joint and muscle weakness. If hemodialysis patients feel unwell after dialysis, it is recommended to go to regular hospitals in time, improve the examination to clarify the cause of the disease, and then give targeted treatment under the guidance of doctors.