Abstract: Objective To analyze the significance of procalcitonin (PCT) and C reactive protein (CRP) in the diagnosis of children's fever aged 1-3 months.Methods From January 2016 to January 2017, 135 children aged 1-3 months with fever who treated in maternal and child care hospital of Shenzhen were selected as objects, and they were divided into bacterial infection group and virus infection group according the final diagnosis. At the same period, 60 normal physical examination children were selected as control group. The contents of PCT, CRP and routine blood count (WBC) were measured among of the children.Results Compared with viral infection group, the levels of PCT, CRP and WBC in the serum of the children in bacterial infection group were higher obviously. The serum levels of PCT and CRP were positive in children with fever in bacterial infection group and the positive rates were 93. 65% and 84. 13%, which was higher than that of WBC (73. 02%). The specificity of PCT and CRP as criterion were 88. 89%and 54. 17% respectively, and the difference was statistically significant (χ²=21. 312, P< 0. 01). The specificity of WBC was 47. 22% (34/72), which was lower than the specificities of PCT and CRP.Conclusion The determination of PCT and CRP in serum in children aged 1-3 months with fever is conductive to rapidly determine the cause of fever and is suitable for clinical application.