Objective: To assess the value of urine soluble triggering receptor expressed on myeloid cells-1(sTREM-1) in early diagnosis and prognosis of sepsis associated acute kidney injury (AKI). Methods: This was a case-control study. A total of 62 patients with sepsis during November 2016 to June 2017 were collected, who were divided into non-AKI sepsis (n= 49) and AKI sepsis (n=13) groups according to the serum creatinine (SCr) or urine output, sepsis with shock (n=22) and sepsis without shock (n=40) groups according to the presence of shock, survival (n=47) and death (n=15) groups according to the mortality. Twenty healthy children were recruited in control group, whose urine sTREM-1 were used as reference value. Urine and blood specimens were detected on admission (within 12 h), at 24 h and 48 h after admission. Student's t-test and Mann-Whitney U test were used for statistical analysis. Results: On admission, the level of urine sTREM-1 were significantly higher in sepsis patients than in healthy controls (96.8 (71.3, 105.8) vs. 68.6 (60.6, 71.1)ng/L, Z=4.708, P<0.05). Comparing of sTREM-1 in different groups showed that the levels were higher in AKI sepsis patients than in the non-AKI ones ((106±5) vs. (86±18) ng/L, t=6.670, P<0.05), higher in the sepsis with shock group than in sepsis without shock group ((98±11) vs. (86± 20) ng/L, t=3.059, P<0.05), and also higher in death group than in survival group ((101±12) vs. (87±18) ng/L, t=3.615, P<0.05). The area under the receiver operating characteristic (AUROC) of urine sTREM-1 in predicting sepsis associated AKI was 0.814 (95%CI: 0.708-0.920), which was higher than that in predicting shock, increased serum creatinine, hyperlipidemia or hyperbilirubinemia (0.530, 0.425, 0.429 and 0.443, respectively). The optimal sTREM-1 cut-off point for predicting sepsis associated kidney injury was 96.5 ng/L, with specificity and sensitivity of 100% and 57.1%. The odds ratio(OR) of urine sTREM-1 was 0.879 with a significance of 0.005 after adjusting shock, prognosis, serum creatinine, lactate and total bilirubin level, indicating that the urine sTREM-1 was an independent risk factor of sepsis associated AKI. Conclusion Urine sTREM-1 can be used as an early diagnostic biomarker for sepsis associated AKI, with advantage of noninvasiveness and convenience. Trial registration: Chinese Clinical Trial Registry, ChiCTR-DDD-17010743.