What the common people call blood washing should be the medical hemodialysis treatment. Hemodialysis treatment is one of the main treatment modalities of renal replacement therapy for patients with acute and chronic renal failure. The equipment has hemodialysis machine, water treatment system, dialyzer, dialysis solution, etc. By leading the blood of the patient out of the body, it exchanges substances in the dialyzer through the principles of diffusion, convection, ultrafiltration and adsorption, removes metabolites and toxins in the patient’s body, and maintains the balance of water, electrolytes, acid-base balance. At the same time, it can also ultrafiltrate excessive water and return the purified blood to the patient’s body. Hemodialysis treatment is very mature so far, and it has brought good news to the majority of uremic patients and patients with acute renal insufficiency.