Objective To investigate the clinical application of procalcitonin (PCT),pre-albumin (PA)and white blood cell (WBC)detections in children infectious diseases.Methods 116 children inpatients of infectious diseases in our hospital were select-ed for conducting the study and divided into the non-bacterial infection group (56 cases)and the bacterial infection group (60 cases) according to the different pathogenic microorganisms.Other 64 children with healthy physical examination in the outpatient depart-ment were taken as the control group.The blood PCT,PA levels and WBC count were detected in 3 groups,and which before and after treatment in the bacterial infection group were detected.The differences in PCT,PA levels and WBC count were compared a-mong the groups.Results The blood PCT level and WBC count in the bacterial infection group and the non-bacterial infection group were all higher than that in the control group,while the PA level in the bacterial infection group was lower than that in the non-bacterial infection group and the control group,the differences had statistical significance (P <0.05);the PCT level and WBC count after treatment in the bacterial infection groups were lower than those before treatment,while the PA level after treatment was higher than that before treatment with statistical difference (P <0.05).Conclusion The detection of PCT,PA and WBC count can be used as the indexes for diagnosing infectious diseases in children,and provides reference for the judgment of prognosis.