Continuous renal replacement therapy (CRRT) is one of the most important treatment approaches in critically illpatients. It has been applied widely, not only limited in replacement therapy of acute kidney injury (AKI), but also extended to multiple organ function support therapy. Rational anticoagulation is one of the key points to achieve therapeutic effect. However, in critical patients, it is also a challenge because a large number of patients are under the risk of severe hemorrhage and hemostasis due to serious infection and inflammatory response. No anticoagulation will decrease the filter function and survival, which will impair the treatment effect. There are many anticoagulant methods, among whicheachprotocol is a double-edged sword. Individual anticoagulation approach selection should consider the characteristics of patients and the resources and experiences of the intensive care unit.