Objective To observe the changes of soluble triggering receptor expressed on myeloid cell-1 (sTREM-1)and inflammatory mediators in serum of senile patients with hospital-acquired pneumonia and explored the state of local inflammatory response in HAP. Methods Twenty senile patients with HAP and twenty healthy controls were in-cluded. Serum sTREM-1, nuclear factor-κB (NF-κB) and interleukin-8 (IL-8) were detected on day 1, 5, 10. Com-bined with CPIS score to analyze the correlation of these indicators and the severity and prognosis of pneumonia. Re-sults The concentrations of sTREM-1, NF-κB and IL-8 in serum were significantly higher than those in controls. There was a significant positive correlation between the sTREM-1, NF-κB and IL-8 and CPIS score. Conclusion sTREM-1, NF-κB and IL-8 is a good marker in diagnosing pneumonia. The levels of sTREM-1, NF-κB and IL-8 have a positive correlation with severity of HAP.