The purpose of hemodialysis is to replace some of the functions lost in renal failure, it can play the following roles: 1, remove metabolic wastes, such as creatinine, urea, amines, phenols, etc. Long Hua, Department of Endocrine Nephrology, Baicheng Hospital 2, regulate the water balance. Uremic patients are mostly swollen due to sodium and water retention, through hemodialysis ultrafiltration dehydration, can gradually reduce swelling to dry weight. 3.Regulate electrolyte balance. For example, patients with high potassium can achieve the purpose of potassium reduction through hemodialysis. 4.Regulate the acid-base balance. Uremic patients have acidosis of varying severity, and hemodialysis can correct acidosis. However, hemodialysis cannot replace the endocrine function of the kidney. Therefore, uremic patients also need erythropoietin and antihypertensive drugs and other treatments during hemodialysis.