Background <p>Liver transplantation (LT) is the most effective treatment for acute-on-chronic liver failure (ACLF). Current transplant evaluation systems predominantly rely on the Model for End-Stage Liver Disease (MELD) score, which has limitations in prioritizing patients on the waiting list. This study aimed to evaluate the prognostic utility of MELD-based scores (MELD, MELD-Na, iMELD) in HBV-ACLF to optimize organ allocation.</p> Methods <p>In this observational study, we retrospectively analyzed 205 patients hospitalized with HBV-ACLF between January 2018 and January 2022. ACLF was diagnosed according to APASL criteria, and transplant listing followed EASL clinical practice guidelines.</p> Results <p>We calculated the MELD series score and transplantation-free survival at 30-, 90-and 180-day for HBV-ACLF patients on the transplant waiting list. It was found that the iMELD is superior to MELD and MELD-Na in evaluating the prognosis of patients waiting for transplantation. In the non-transplant scenario, the 30-day, 90-day and 180-day survival rates of HBV-ACLF patients with iMELD &lt; 39.79 were 95.65% (88/92), 93.48% (86/92), and 92.39% (85/92), respectively. The results were statistically significant among the three groups (P &lt; 0.05). Therefore, for HBV-ACLF patients who met the transplantation conditions (MELD ≥ 15) and iMELD &lt; 39.79, temporary artificial liver and standard medical treatment can be performed when liver transplantation is not performed in time. Additionally, age and hepatic encephalopathy grade were identified as independent risk factors for mortality in non-transplant management.</p> Conclusions <p>The iMELD score outperforms MELD and MELD-Na in prognostic assessment of ACLF. For waitlisted ACLF patients with iMELD &lt; 39.79 who cannot undergo immediate transplantation, temporary SMT and ALSS therapy represent a viable bridging strategy.</p>