Abstract: Objective To explore the clinic applications of procalcitonin(PCT), CD64 and C-reactive protein (CRP) in the diagnosis of infectious disease. Methods Patients with bacteria and virus infection were divided into two groups:bacterial and viral. And people receiving health examination were allocated into control group. PCT, CD64 and CRP were detected seperately in each group. Results PCT, CD64 and CRP were higher in bacterial infection group than those in health group, while only CRP was higher in viral infection group than that in control group. The positive rates of PCT, CD64 and CRP were higher than control, which were 59.5%, 76.2% and 52.3%, and only the CRP was higher in bacterial infection group with the rate being 47.6%. The CD64 ROC curve had the largest area of square under. Conclusion PCT and CD64 are more specific than CRP in bacterial infection disease. CD64 is a very valuable indication in the diagnosis of bacterial infection disease.