Acute-on-chronic liver failure (ACLF) is a complex clinical syndrome characterized by acute liver function decompensation on the basis of chronic liver diseases, with organ failure and a high short-term mortality rate. The course of ACLF varies across patients, and the disease is reversible. Patients tend to have diverse long-term outcomes, and clinicians should evaluate the prognosis of patients as early as possible to optimize treatment regimen and improve survival rate. This article describes the following five grades of the long-term prognosis of patients with ACLF for the first time: grade Ⅰ is the ideal outcome of no cirrhosis; grade Ⅱ is the satisfactory outcome of compensated liver cirrhosis manifesting as reversible liver cirrhosis or persistent compensated liver cirrhosis; grade Ⅲ is the acceptable outcome of decompensated liver cirrhosis manifesting as decompensated liver cirrhosis or chronic liver failure; grade Ⅳ is the outcome of survival after transplantation; grade Ⅴ is the outcome of death. This article aims to provide a reference for judging long-term clinical prognosis.