Objective To establish a new prognostic model, MACLF, for predicting the short-term prognosis of hepatitis B virus-associated acute-on-chronic liver failure (HBV-ACLF) , and to investigate its value in predicting the short-term prognosis of HBV-ACLF.Methods A retrospective cohort study was performed for the clinical data of 270 patients with HBV-ACLF who were admitted to The First Affiliated Hospital of Nanchang University from January 2015 to November 2018. The patients were divided into survival group with 153 patients and death group with 117 patients according to their conditions after 3 months of treatment, and influencing factors for the short-term prognosis of HBV-ACLF were analyzed. The chi-square test was used for comparison of categorical data between two groups, A binary logistic regression analysis was performed for statistically significant indices determined by multivariate analysis and a model was established.and the Mann-Whitney U test was used for comparison of continuous data between two groups. A binary logistic regression analysis was used for multivariate analysis, a binary logistic regression analysis was performed for statistically significant indices determined by multivariate analysis and a model was established, and the receiver operating characteristic (ROC) curve was plotted to evaluate the value of MACLF in predicting the short-term prognosis of HBV-ACLF. Results The univariate analysis showed that there were significant differences between the survival group and the death group in free triiodothyronine (FT3) , thyroid stimulating hormone, international normalized ratio, neutrophil-lymphocyte ratio (NLR) , platelet count (PLT) , alanine aminotransferase, aspartate aminotransferase-alanine aminotransferase ratio, total bilirubin (TBil) , albumin, creatinine, total cholesterol, triglyceride, sodium, alpha-fetoprotein, serum ferritin, Child -Turcotte-Pugh (CTP) class, Model for End-Stage Liver Disease (MELD) score, and complications (hepatic encephalopathy, hepatorenal syndrome, spontaneous peritonitis, gastrointestinal bleeding, and pulmonary infection) (all P < 0. 05) . The multivariate analysis showed that TBil (odds ratio [OR]= 1. 007, P = 0. 001) , INR (OR = 5. 750, P < 0. 001) , FT3 (OR = 0. 084, P = 0. 003) , PLT (OR =0. 987, P = 0. 022) , hepatorenal syndrome (OR = 7. 146, P = 0. 045) , and pulmonary infection (OR = 3. 816, P = 0. 023) were independent influencing factors for the short-term prognosis of HBV-ACLF. Therefore, a new model of MACLF was established for the short-term prognosis of HBV-ACLF: Logit (P) = 0. 007 ×[TBil (umol/L) ]+ 2. 181 × INR-2. 762 × [FT3 (pg/mL) ]-0. 014 ×[PLT (×109/L) ]+ 1. 797 × [hepatorenal syndrome (with: 1; no: 0) ]+ 1. 339 × [pulmonary infection (with: 1; no: 0) ]-2. 291. The ROC curve analysis showed that MACLF had significantly higher area under the ROC curve (0. 934) and Youden index (0. 774) than CTP class, MELD, and MELD combined with serum sodium concentration. Conclusion The new model of MACLF has a good value in predicting the short-term prognosis of patients with HBV-ACLF after 3 months of treatment.