Objective To assess the value of intheleukin-6 (IL-6) in early diagnosis of children with acute lower respiratory tract bacterium infection . Methods Serum IL-6 levels of 85 children with acute lower respiratory tract infection were detected by ELISA and c-reactive protein (CRP), white blood cells (WBC), ploymorphonuclear (PMN) were measured in acute phase. Results When indices above were judged independently ,the reliability of IL-6 was highest with its sensitivity, specificity, positive predictive value (PPv), negative predictive value (NPV) and Youden’s index being 84% ,94% ,93% ,87% and 0.78 respectively .While united tests were used , diagnosis accuracy of IL-6 combining CRP was superior to classical indices (CRP,WBC,PMN). Conclusions The combination of IL-6 and CRP seems to be a valuable parameter in the early diagnosis of children with acute lower respiratory tract bacterium infection .