ObjectiveTo study the value of procalcitonin (PCT) and highsensitivity Creactive protein (HsCRP) detection in the diagnosis of fever of unknown origin （FUO） in children.MethodsElectrochemiluminescence and immunoturbidimetry method were adopted to detect serum PCT and HsCRP levels, and the values were evaluated according to the final diagnosis.ResultsOf 244 children with FUO, infectious diseases (152 cases, 62.30%),connective tissue diseases (34 cases, 13.93%) and the tumor diseases (20 cases, 8.20%) were the main causes of FUO. Serum PCT, HsCRP levels in children with infectious diseases were (31.65±7.26)μg/L and (17.52±6.43)mg/L respectively, which was significantly higher than those of the normal control group(［0.31±0.28］μg/L and ［1.87±0.31］mg/L respectively, both P<0.01); serum PCT and HsCRP level in children with noninfectious diseases was (0.52±0.51)μg/L and (1.96±0.45)mg/L respectively, there were no significant difference compared with the normal control group(both P<0.05). Of all infectious diseases, serum PCT and HsCRP levels were the highest in patients with bacterial infection(［43.24±8.34］μg/L,［26.74±7.05］mg/L, respectively), the next was in patients with Mycoplasma/Chlamydia infection(［6.72±1.65］μg/L, ［15.05±2.79］mg/L, respectively), virus infection didn’t change obviously(［0.34±0.26］μg/L, ［1.89±0.66］mg/L, respectively)；positive diagnosis rate of simultaneous detection of PCT and HsCRP (92.63%) was significantly higher than that of PCT (84.21%) or HsCRP(68.42%) alone (both P<0.01).ConclusionCombination detection of serum PCT and HsCRP can improve the early diagnosis of FUO, distinguish infectious fever from noninfectious fever, bacterial from viral infection，which is beneficial to timely diagnosis and treatment of FUO in children.