Objective:To research the clinical effects of ulinastatin in the treatment of sepsis induced acute renal injury and its possible mechanisms.Methods:114 cases of patients with sepsis induced acute kidney injury from 2014.02 ～ 2016.08 were selected and randomly divided into the control group (n=57) and experimental group (n=57) according to the draw method,the control group was given conventional treatment,while the experimental group was treated by ulinastatin based on the control group,the urine urinary injury molecule-1 (KIM-1),atrialnatriuretic peptide (ANP),cyscatin-c (CYS-C),interleukin l,6 (IL-1,IL-6),c-reactive protein (CRP),tumor necrosis factor-α(TNF-α),nitric oxide (NO),endothelin 1 (ET-1),immunoglobulin A,G,M (IgA,IgG,IgM) levels,APACHE-Ⅱ score were compared between two groups before and after the treatment.Results:After treatmented,the urine of KIM-1,ANP,serum of CYS-C,IL-l,IL-6,CRP,TNF-α,ET-1 levels and APACHE-Ⅱ score of experimental group were significantly lower than those of the control group (P＜0.05).The serum NO,IgA,IgG,IgM levels of experimental group were significantly higher than those of the control group (P＜0.05).Conclusion:Ulinastatin could significantly relieve sepsis induced acute renal injury,which might be related to the inhibition of inflammatory response,improvement of the renal blood flow and immune function.