Objective To observe the change of serum fibrinogen(FIB) ,procalcitonin(PCT) and hypersensitve C reactive protein (hs-CRP) in children with infectious pneumonia and its clinical significance .Methods One hundred and four cases of children with bacterial infectious pneumonia (bacterial group) ,109 cases with non-bacterial infectious pneumonia(non-bacterial group) and 110 healthy children under going physical examination (control group) were included into this study ,the serum FIB ,PCT and hs-CRP level were observed in each group .Results The FIB ,PCT and hs-CRP levels in the bacterial group were higher than those in the non-bacterial group and control group (P<0 .05);the FIB ,PCT and hs-CRP had no statistical difference among the virus group , mycoplasma group and chlamydia group had no atoctistical(P>0 .05) .The positive rate of combined detection of FIB ,PCT and hs-CRP in the non-bacterial group and bacterial group was significantly higher than that of single index detection (P<0 .05) .The FIB level in the bacterial group was positively correlated with PCT and hs-CRP(r=0 .445 ,0 .396 ,P<0 .05) .PCT and hs-CRP showed a positive correlation (r=0 .487 ,P=0 .021) .Conclusion The combined detection of FIB ,PCT and hs-CRP can effectively identify bacterial infection and non-bacterial infection and which has an important clinical significance for the diagnosis and treatment of pathogenic infection of pneumonia .