ObjectiveTo investigate the influence of different diagnostic criteria on the short-term prognosis of patients with acute-on-chronic liver failure （ACLF）. MethodsA total of 115 ACLF patients who were hospitalized in Department of Gastroenterology， The Second Affiliated Hospital of Kunming Medical University， from January 2018 to January 2022 were enrolled， and all patients received internal medical treatment combined with artificial liver therapy. According to the guidelines， the patients were divided into CMA guideline group （Diagnostic and treatment guidelines for liver failure by Chinese Medical Association）（n=100）， APASL guideline group （Consensus statements of Asian Pacific Association for the Study of the Liver）（n=94）， and EASL guideline group （Criteria proposed by European Association for the Study of the Liver）（n=36）. The above three guidelines were compared in terms of 90-day mortality rate. A one-way analysis of variance was used for comprision of continuous date between groups； the chi-square test was used for comprision of categorical date between groups. The receiver operating characteristic （ROC） curve of related variables. ResultsThe 90-day mortality rate was 50.0% in the CMA guideline group， 51.1% in the APASL guideline group， and 77.8% in the EASL guideline group， and the EASL guideline group had a significantly higher 90-day mortality rate than the CMA guideline group （χ²=8.351， P=0.004） and the APASL guideline group （χ²=7.650， P=0.006）. EASL guideline had a sensitivity of 22.2% and a specificity of 92.3% in predicting the risk of short-term mortality， with an area under the ROC curve was 0.576. ConclusionACLF patients who meet EASL guideline tend to have a worse short-term prognosis， and this guideline may help to identify patients at a relatively high risk of short-term death.