Objective To investigate the diagnostic value of procalcitonin (PCT) ,C‐reactive protein(CRP) and white blood cell (WBC) count in children with respiratory tract infection .Methods A total of 358 children inpatients with respiratory tract infec‐tion in the pediatric department of our hospital from 2014 January to June 2015 were selected and divided into the bacterial infection group and non‐bacterial infection group according to the throat swabs and sputum culture results .The venous blood was collected before and after treatment for detecting PCT ,CRP and WBC count ;meanwhile 30 healthy children were selected as the control group .Results The PCT ,CRP and WBC levels in the bacterial infection group were significantly increased compared with the non‐bacterial infection group and control group(P<0 .01) ,while which in the non‐bacterial infection group were relatively close to those in the control group(P>0 .05);but the PCT ,CRP and WBC count levels after 1‐week treatment in the bacterial infection group were significantly decreased compared with before treatment (P<0 .01) ,while which in the non‐bacterial infection group had little change between before and after treatment (P>0 .05) .Conclusion The combined detection of PCT ,CRP and WBC count has an important application value in the differential diagnosis and medication guidance of the children′s respiratory tract infection .