Continuous renal replacement therapy (CRRT), also known as continuous blood purification (CBP). In 1995, the First International Conference on Continuous Renal Replacement Therapy (CRRT) defined CRRT as a form of purification in which impaired kidney function is replaced by a continuous blood purification therapy for 24 hours or nearly 24 hours per day. Continuous renal replacement therapy includes continuous arteriovenous and static venous hemodiafiltration (CAVH, CVVH), continuous arteriovenous and static venous hemodialysis (CAVDH, CVVDH), and continuous arteriovenous and static venous hemodialysis filtration (CAVHDF, CVVHDF). In recent years, the concept of “intermittent CRRT” and continuous daytime renal replacement therapy has been introduced, which means that the daily treatment time is 8-12 hours to ensure effective treatment and sufficient rest time for the patient. CRRT, together with vital sign monitoring, mechanical ventilation and extracorporeal membrane lung, are called the “three life support technologies” for critically ill patients. Our department has achieved great success in successfully using CRRT to save critically ill children. This new technology is mainly used for acute renal failure, severe sepsis, drug and toxic poisoning, various severe autoimmune diseases, acute liver failure, acute cardiac failure and severe cerebral edema in children.