Objective To investigate the clinical value of geriatric nutrition risk index (GNRI), systemic immune inflammation index (SII) and triglyceride glucose (TyG) index in elderly patients with acute pancreatitis (AP). Methods A total of 161 elderly AP patients admitted to our hospital from January 2020 to December 2022 were recruited, and according to their severity, they were divided into mild (MAP, n=73), moderate severe (MSAP, n=42) and severe AP (SAP, n=46) groups. Based on the outcomes, the 46 SAP patients were further divided into death (n=17) and survival (n=29) subgroups. The GNRI, SII, and TyG index were compared among each group and subgroup. SPSS statistics 22.0 was used for data analysis. Depending on data type, one-way ANOVA, SNK-q test, student′s t test, or Chi-square test was used for inter group comparison. Receiver operating characteristic (ROC) curve was plotted to analyze the value of GNRI, SII and TyG index in predicting SAP occurrence and death in the elderly. Results The SAP group had significantly lower GNRI [(84.62±3.73) vs (88.75±6.10) and (92.80±8.06)], and higher SII [(2 738.74±1 068.15) vs (1950.42±987.82) and (1 293.27±719.50)] and TyG index [(7.92±1.26) vs (6.47±1.02) and (4.60±0.53)] when compared with the MSAP and MAP groups (all P<0.001). Significantly lower GNRI [(82.40±3.10) vs (87.53±4.92)], but higher SII [(3 160.94±1 207.15) vs (2 318.50±1002.53) ]and TyG index [(9.36±1.42) vs (6.75±1.16)] were observed in the death subgroup than the survival subgroup (all P<0.001). ROC curve analysis showed that area under the curve (AUC) of the three indicators combined together in predicting SAP occurrence and death were 0.857 (95%CI 0.798-0.916) and 0.910 (95%CI 0.848-0.971), respectively. Conclusion GNRI, SII, and TyG index are related to the severity and prognosis of AP, and the combination of these three indictors has high clinical value in diagnosis of SAP and prediction of death in elderly AP patients.