Background and Aims Paeoniflorin is an important traditional Chinese medicine with broad-spectrum anti-inflammatory properties. However, its role in protecting kidney function in acute necrotizing pancreatitis (ANP)-related renal injury remains unclear. Therefore, this study was conducted to investigate the effects of paeoniflorin on ANP-related renal injury and its action mechanism.Methods SD rats were randomly divided into a sham surgery group, an ANP model group (ANP group), and an ANP model plus paeoniflorin treatment group (paeoniflorin group). ANP was induced by retrograde injection of 5% sodium taurocholate into the biliopancreatic duct, and paeoniflorin was injected via the femoral vein after modeling. Initially, different doses of paeoniflorin (50, 100, 150 mg/kg) were tested to determine the optimal dosage based on their effects on serum amylase (AMY), lipase (LIPA), and liver function indicators. Subsequently, the optimal dose of paeoniflorin was used for intervention, and at different time points after modeling (3, 6, 12 h), the groups were evaluated for pancreatic and renal tissue histopathological changes, serum inflammatory markers, AMY, LIPA, urea nitrogen (BUN), and creatinine (Cr) levels. In renal tissues 12 h after modeling of all groups, immunohistochemistry was employed to examine the expression of NF-κB and caspase-3, TUNEL assay was used to detect cell apoptosis, and Western blot was performed to analyze the expression of p38 and phosphorylated p38 (p-p38).Results The dose-response analysis revealed that 100 mg/kg was the optimal dosage of paeoniflorin. Subsequent experiments showed that compared to the sham surgery group, both the ANP group and the paeoniflorin group exhibited varying degrees of ANP and renal injury histopathological changes (increased histopathological scores), elevated inflammatory markers (TNF-α, IL-1β, IL-6), increased serum enzyme indicators (AMY, LIPA) and renal function indicators (BUN, Cr) after modeling, which worsened over time. However, the paeoniflorin group showed significantly lower levels of all these variables at each time point than the ANP group (all P<0.05). In renal tissues 12 h after modeling, the expression of NF-κB and caspase-3, the number of apoptotic cells, and the p-p38/p38 ratio were significantly increased in both the ANP group and the paeoniflorin group; however, the extents of increases in the paeoniflorin group was significantly lower than those in the ANP group (all P<0.05).Conclusion Paeoniflorin exerts significant protective effects against ANP-related renal injury. Its mechanism of action involves inhibiting the progression of ANP on the one hand, and on the other hand, it may reduce ANP-related renal damage by suppressing the cascade reaction caused by NF-κB-related inflammatory factors through the reduction of p38 pathway activity.