Abstract: Acute-on-chronic liver failure (ACLF) is an acute deterioration of liver function occurring on the basis of chronic liver disease, accompanied by failure of the liver and extrahepatic organs, and is associated with a high short-term mortality rate. Liver transplantation is the only curative treatment for patients with ACLF. However, the shortage of donor livers and limitations of the organ allocation system mean that only a minority of patients can receive transplants. The current organ allocation system based on the model for end-stage liver disease (MELD) score may underestimate the urgency of liver transplantation for ACLF patients. Therefore, it is urgent to develop better assessment tools to determine which ACLF patients are most likely to benefit from liver transplantation. This article reviews the current mainstream definitions of ACLF, the selection of candidates for liver transplantation in ACLF, and the prognostic scoring systems for liver transplantation in ACLF, both domestically and internationally, in order to provide a reference for the prognostic assessment of liver transplantation in ACLF patients.