Abstract: OBJECTIVE To study the changes and clinical diagnostic significance of serum C reactive protein (CRP) and procalcitonin (PCT) levels in children with sepsis. METHODS A total of 60 patients with bloodstream infection in sepsis from Jan. 2010 to Jun. 2016 in our hospital were selected as sepsis infection group, and another 60 cases of children with other infection during the same period were selected as control group. The serum levels of CRP and PCT were compared between the two groups, PCT was determined using immunofluorescence double antibody sandwich method, and CRP was determined using colloidal gold method. RESULTS The levels of CRP and PCT in sepsis infection group were (138.93±29.31)mg/L and(13.21±1.87)ng/ml respectively, which were significantly higher than (47.34±9.84)mg/L,and(0.31±0.05)ng/ml in control group, and the difference was statistically significant(P＜0.05).The levels of CRP and PCT in the gram-positive bacterial infection were (73.12±17.84)mg/L and (2.31±0.44)ng/ml, which were lower than (116.72±29.79)mg/L and (14.82±1.37)ng/ml in the gram-negative bacterial infection, and the difference was statistically significant(P＜0.05). There were positive correlations between CRP and PCT in gram-positive bacterial infection, gram-negative bacterial infection, and other sepsis patients(r=0.631,0.682,0.564;P＜0.05). CONCLUSION The expression levels of CRP and PCT in children with sepsis are higher than those in children with other infection, and the levels of CRP and PCT in the gram-negative bacterial infection were lower than those in the gram-positive bacterial infection. Combined detection of serum CRP and PCT in children with sepsis bloodstream infection has a high diagnostic value and can be used as a reliable basis for clinical diagnosis and treatment, which is worthy of application and popularization.