Abstract: Objective　To investigate the role of soluble triggering receptor expressed on myeloid cell-l (sTREM-1) in children with community acquired pneumonia. Methods　One hundred and seventy-six children with community acquired pneumonia, 98 cases were mild and 78 cases were servere, were recruited. Thirty healthy children were recruited as control group. The white blood cell count (WBC), neutrophil percentage (N%), C-reactive protein (CRP), procalcitonin (PCT), interleukin-6 (IL-6), interleukin-10 (IL-10), and sTREM-1 were measured. Results　The levels of WBC, N%, CRP, IL-6, IL-10, IL-6/IL-10, PCT, and sTREM-1 were significantly different among children with mild pneumonia, severe pneumonia, and healthy controls. All of the indicators were elevated in children with mild and severe pneumonia than those in healthy controls (P<0.05). IL-6/IL-10 sTREM-1 were further significantly elevated in children with severe pneumonia than children with mild pneumonia (P<0.05). IL-6/IL-10 was positively correlated with sTREM-1 (r=0.42, P<0.05). Conclusions　sTREM-1 may help for evaluating the severity and outcome of children with community acquired pneumonia.