Abstract: OBJECTIVE To observe the clinical value of human neutrophil lipocalin（HNL） in identification of acute bacterial and viral infection. METHODS From Mar 2017 to Dec 2017, totally 123 patients with bacterial infection who were treated in the First Hospital of Jilin University were assigned as the bacterial group, and 63 patients with viral infection were set as the control group, meanwhile, 420 healthy people who received physical examination were chosen as the control group.The levels of serum HNL, C-reactive protein（CRP） and procalcitonin（PCT） of all the study objects were detected, and the clinical values of the above indexes in diagnosis of the acute bacterial infection and viral infection were observed. RESULTS There were significant differences in the levels of serum HNL, CRP and PCT among the three groups of study objects（P＜0.05）; the HNL level of the bacterial group was significantly higher than that of the viral group and the control group（P＜0.05）.The serum HNL level of the viral group was not elevated or elevated slightly, as compared with the control group, there was no significant difference.When the cutoff value was 115.5 ng/ml, the sensitivity and specificity of the HNL were respectively 0.856 and 0.631 in differential diagnosis of acute bacterial infection and viral infection; the area under ROC curve of the HNL was 0.878 in distinguishing between the acute bacterial infection and the viral infection, larger than that of CRP and PCT. CONCLUSION The serum HNL level has high clinical value in identification of the acute bacterial and viral infection, and it is superior to CRP and PCT in the diagnostic efficiency.