Background and objectives:Triggering receptor expressed on myeloid cells-1 (TREM-1) is an important inflammationrelated biomarker. The present study aimed to determine whether this affects the short-term prognosis of patients with acute-chronic liver failure (ACLF). Methods: The serum sTREM-1 levels of 30 healthy subjects (HS), 40 chronic hepatitis patients without cirrhosis and liver failure (CH), 38 liver cirrhosis (LC) patients, and 59 ACLF patients were evaluated by enzyme-linked immunosorbent assay. The predictive accuracy of the logistic model for survival rate within 90 days in patients with ACLF was determined using the area under the receiver operating characteristic curve (AUC).Kaplan-Meier analysis and log-rank test were performed to revalidate the factors l for the 90-day survival rate of patients with ACLF. Results: Compared to the CH, LC and HS groups, the serum sTREM-1 levels of ACLF patients were significantly elevated (p < 0.001). In ACLF patients, the serum sTREM-1 levels further increased in non-survivors (661.51 [494.36-1,028.82] pg/mL), when compared to the survivors (440.92 [308.00-523.21] pg/mL) (p = 0.002). The multivariate logistic regression analysis indicated that serum sTREM-1, sodium, and the international normalized ratio (INR) were independent predictors for the 90-day mortality of patients with ACLF. The AUC value for logit (p) in predicting the 90-day prognosis of ACLF patients was 0.89 (0.78-1.00), with a sensitivity of 70%, a specificity of 89.74%. Conclusions: Serum sTREM-1 is a valuable independent factor for determining the 90-day mortality of ACLF patients. Combining the INR and sodium in the logistic regression model may improve the accuracy in predicting the prognosis.