Abstract: Neutrophil CD64 expression can be used for the early diagnosis of infectious disease caused by bacterial infection, such as sepsis, respiratory infections, burns and postoperative infection and the differential diagnosis of activity and infection in autoimmune inflammatory disease. The division of different threshold, neutrophil CD64 expression can also be applied to judgment of activity and severity in noninfectious inflammatory disease. If combine with other inflammatory indexes, the diagnostic sensitivity and specificity can be improved and CD64 detection can be better used for identify bacterial infection and virus infection. Neutrophil CD64 expression is helpful for disease assistant diagnosis, condition monitoring, prognosis judgement, curative effect evaluation, guidance of clinical usage of drugs and has a broad prospect in the clinical application.