Objective: To explore and analyze the prognostic value of serum expression of microRNA-330-5p (miR-330-5p), microRNA-140-5p (miR-140-5p), and microRNA-214-5p (miR-214-5p) in patients with sepsis acute kidney injury (AKI). Methods: A total of 186 patients with sepsis-induced AKI, 186 patients with sepsis alone, and 186 healthy volunteers who underwent physical examinations during the same period were selected from Affiliated Hospital of Tangshan Vocational and Technical College from January 2022 to January 2024 as the research subjects and were respectively included in the AKI group, the non-AKI group, and the healthy group. Among the AKI group, 115 cases survived within 28 days of treatment (included in the survival group), and 71 cases died (included in the death group). The expression levels of miR-330-5p, miR-140-5p, and miR-214-5p in the serum of the three groups were detected by qRT-PCR; the correlations between miR-330-5p, miR-140-5p, miR-214-5p and APACHE Ⅱ score, SOFA score were analyzed by Spearman method. Multivariate logistic regression model was applied to analyze the influencing factors of death within 28 days of treatment in sepsis AKI patients. ROC curve was applied to analyze the prognostic value of miR-330-5p, miR-140-5p, and miR-214-5p in evaluating death within 28 days of treatment in sepsis AKI patients. Results: The levels of serum miR-330-5p and miR-140-5p in AKI patients were lower than those in non-AKI patients and healthy individuals, while the level of miR-214-5p was higher (P<0.05). The levels of serum miR-330-5p and miR-140-5p in AKI patients at stage 1, 2, and 3 showed a decreasing trend, while the level of miR-214-5p showed an increasing trend (P<0.05). The APACHE II score, SOFA score, PCT, and miR-214-5p level in the death group were higher than those in the survival group, while the oxygenation index, miR-330-5p, and miR-140-5p levels were lower (P<0.05). In AKI patients, miR-330-5p and miR-140-5p were negatively correlated with the APACHE II score and SOFA score, while miR-214-5p was positively correlated with them (P<0.05). The oxygenation index, miR-330-5p, and miR-140-5p were protective factors, while the APACHE II score, SOFA score, PCT, and miR-214-5p were risk factors (P<0.05). The area under the curve (AUC) for predicting death in sepsis patients with AKI by miR-330-5p, miR-140-5p, and miR-214-5p was 0.839, 0.827, and 0.844, respectively. The AUC for the combined prediction of the three was 0.927, which was superior to the AUC of the individual predictions of miR-330-5p, miR-140-5p, and miR-214-5p (ZmiR-330-5p=2.601, ZmiR-140-5p=2.750, ZmiR-214-5p=2.230, P<0.05). Conclusion: Serum miR-330-5p and miR-140-5p are down-regulated in patients with sepsis accompanied by AKI, while miR-214-5p is up-regulated. The three are closely related to patient prognosis, and their combination can effectively predict prognosis and death in patients with sepsis accompanied by AKI.