The differences between plasma exchange and blood perfusion are as follows: 1. Plasma exchange is mainly used to treat immune diseases such as systemic lupus erythematosus and ANCA-associated small vessel vasculitis. While hemoperfusion is mainly used for medium and large molecule toxin removal, treatment of drug poisoning, acute pancreatitis and other diseases; 2. Plasma replacement means using plasma separator to divide the patient’s whole blood into two parts: plasma and blood, while hemoperfusion is the patient’s whole blood passing through the perfusion device, and large molecule toxin is adsorbed in the perfusion device, and whole blood is not separated.