OBJECTIVE: Blood urea nitrogen to albumin ratio (BAR) has served as a predictive marker for patients in the Intensive Care Unit (ICU), and has been studied in patients with sepsis, post-cardiac surgery, severe COVID-19, and acute exacerbation of chronic obstructive pulmonary disease (AECOPD). This objective indicator has demonstrated capability in prognostic prediction.However, research on the prognostic value of BAR in acute pancreatitis (AP) patients are scarce,the goal was to explore the relationship between BAR and total mortality in AP admitted to ICU. METHODS: A Retrospective analysis was performed utilizing the Medical Information Market for Intensive Care (MIMIC IV) database. Patients with AP admitted to ICU were included and grouped based on BAR. Univariate and multivariate Cox regression analysis were utilized to explore the relationship between BAR and total mortality. The area under the curve (AUC) of the receiver operating characteristic (ROC) curve was applied to assess the predictive value of BAR. Cumulative hazard risk accumulation curve verified BAR's predictive capability for short- and long-term mortality. Heterogeneity between different subgroups was excluded by subgroup analysis. RESULTS: Total 514 AP patients were divided into high-BAR (BAR ≥ 7.62) and low-BAR group (BAR < 7.62). The duration of ICU stay was significantly extended in the high BAR group. In the Cox proportional hazard model, whether adjusting for confounding factors or not, the high BAR was an independent risk factor for total mortality. AUC for BAR was 0.78 (95% C1: 0.72-0.84) at 28 days and 0.70 (95%: Cl: 0.64-0.75) at 360 days. CONCLUSION: BAR is an objective and independent predictor of both short- and long-term total mortality in AP patients. A prompt, efficient, and uncomplicated assessment of the severity and prognosis, which facilitates ICU doctors to develop treatment plans for poor patient outcomes.