Objective: To investigate the effect of Monotropein (MON) on sepsis-associated acute kidney injury induced by cecum ligation and puncture (CLP) in mice and the underlying mechanisms. Methods: A total of 90 BALB/c mice were divided into a negative control (NC) group, a Sham group, a CLP group, a CLP+MON group, a Sham+MON group, and a CLP+ dexamethasone (DEX) group. Drug or equivalent saline was injected intraperitoneally once daily for 5 consecutive days after CLP. After all mice were euthanized on day 5, serum and kidney tissues were collected for subsequent experiments. Blood Urea Nitrogen (BUN) and creatinine (CRE) concentrations in serum were detected by biochemical kits, as well as renal oxidative stress related indicators such as Glutathione (GSH), Catalase (CAT), glutathione (GSH), Total Antioxidant Capacity (T-AOC) and Malondialdehyde (MDA) levels. The pathological changes of renal tissues were observed by H&E staining, and the levels of reactive oxygen species (ROS) in renal tissues stained with dihydroethidium (DHE) were observed by laser confocal microscopy. The levels of tumor necrosis factor-α (TNF-α), interleukin-1β (IL-1β) and interleukin-6 （IL-6） in serum and kidney tissues were detected by enzyme-linked immunosorbent assay (ELISA) and real-time fluorescent quantitative polymerase chain reaction (RT-qPCR). Western blot was used to detect the protein expressions of NLRP3 inflammasome and NF-κB signaling pathway. In addition, lipopolysaccharide (LPS)/adenosine triphosphate (ATP) was used to induce HK-2 cells to establish an in vitro sepsis model. Cell experiments were divided into NC group, LPS/ATP group, LPS/ATP+MON group, NLRP3OE + LPS/ATP+MON group and IKKβOE + LPS/ATP+MON group. CCK-8 was used to detect the cell viability, and ELISA was used to detect the secretion of inflammatory cytokines in HK-2 cells. Results: Compared with the CLP group, the survival rate of mice in the CLP+MON group was significantly increased, the appearance of renal tissue was restored from black to bright red, the serum BUN and CRE levels were significantly decreased, and the abnormal pathological changes of renal tissue with increased inflammatory cells were significantly improved. Compared with the CLP group, the levels of TNF-α, IL-1β, and IL-6 were significantly decreased, GSH, CAT, and T-AOC levels were increased, and MDA and ROS levels were significantly decreased in the MON treatment group. Western blot results showed that compared with the CLP group, the expressions of NLRP3, Caspase-1, Cleaved-Caspase-1p20, and p-NF-κB P65 protein in the CLP+MON group decreased significantly, and the expression of IκBα increased significantly. In addition, NLRP3OE + LPS/ATP+MON group and IKKβOE + LPS/ATP +MON group activated NLRP3 inflammasome and NF-κB pathway, and reversed the inhibitory effect of MON on inflammatory cytokines in LPS/ATP-stimulated HK-2 cells compared with LPS/ATP+MON group. Conclusion: MON reduces the release of inflammatory factors by inhibiting the NF-κB/NLRP3 inflammasome pathway to improve sepsis-associated acute kidney injury and dysfunction.