What the 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 includes hemodialysis machine, water treatment system, dialyzer, dialysis solution, etc. By drawing the blood out of the patient’s body and exchanging substances in the dialyzer through the principles of diffusion, convection, ultrafiltration and adsorption, it removes metabolites and toxins from the patient’s body and maintains water, electrolyte and acid-base balance. It also ultrafiltrates excess water and returns the purified blood to the patient. Hemodialysis treatment is very mature so far, and it has brought a boon to the majority of uremic patients and patients with acute renal insufficiency.