Abstract: Objective To analyze the clinical characteristics and peripheral blood characteristics of influenza A and B (hereinafter referred to as influenza)in children, especially the significance of neutrop hil-to-lymphocyte ratio (NLR), in order to improve the understanding level of influenza in children and provide reference for early diagnosis of influenza in children. 
Methods A total of 428 children with fever and/or upper respiratory tract infection were selected. According to the results of influenza virus antigen, they were divided into influenza A virus (IAV) positive group (IAV group, n=172), influenza B virus (IBV) positive group (IBV group, n=132) and control group (n=124).The epidemiological characteristics, clinical manifestations and routine examination results of peripheral blood were reviewed and analyzed. 
Results There were no significant differences in while blood cell (WBC) levels among the three groups (P＞0.05). The levels of neutrophils, lymphocytes， NLR and C-reactive protein(CRP) in peripheral blood of IAV group and IBV group were significantly different from those of control group, respectively (P＜0.05). However, there was no significant difference in neutrophils, lymphocytes, NLR, and CRP between IAV group and IBV group (P＞0.05). 
Conclusion The proportion of neutrophils, lymphocytes， CRP and NLR in peripheral blood routine can provide reference for early diagnosis of influenza in children. 

Key words: influenza, human, disease characteristics, child