Objective To investigate the diagnostic value of combined detection of procalcitonin (PCT), C-reactive protein (CRP), white blood cell (WBC), and neutrophil percentage (NEU%) in bloodstream infection with gram-positive coccus(G+), gram-negative bacillus (G-)and fungus.Methods Detection results of positive blood culture of 389 patients in a hospital between January 2014 and December 2015 were analyzed retrospectively, according to the results of blood culture, patients were divided into G+ coccus, G-bacillus and fungal bloodstream infection groups, inflammatory indicators of different groups of patients were compared.Results Mann-Whitney U test revealed that PCT level of G-infection group was higher than that of G+ and fungal infection group (comparison between G-infection group and G+ infection group : Z=-2.68,P<0.01;comparison between G-infection group and fungal infection group: Z=-2.46,P<0.05).If PCT≥0.5 ng/mL, CRP≥5.0 mg/L, NEU%≥70% and WBC≥10×109/L were as the cut-off point, statistical analysis revealed the positive rate of PCT in G-infection group was higher than that in G+ and fungal infection group(comparison between G-infection group and G+ infection group:χ2=5.94,P<0.05;comparison between G-infection group and fungal infection group:χ2=7.721,P<0.01);the positive rate of CRP in G-infection group was higher than that in G+ infection group (χ2=5.03,P<0.05).Binary logistic regression was adopted to analyze the efficacy of four indicators for the differentiation of bloodstream infection caused by G+ coccus, G-bacillus, and fungus, only PCT had significant difference in the identification of bloodstream infection caused by G-bacillus, G+ coccus and fungus(P<0.01).Conclusion PCT has high accuracy in differentiating G-bacillus, G+ coccus, and fungus of blood culture, dynamic monitoring of PCT combined with detection results of CRP, WBC, and NEU%, patient's condition can be judged rapidly, and antimicrobial agents can be used rationally, so the mortality of patients with bloodstream infection can be reduced.