【Abstract】 Objective To explored the expression and clinical significance of Wip1 in peripheral blood neutrophils in children with bacterial pneumonia. Methods 60 children with bacterial pneumonia and healthy children diagnosed in our hospital from January 2016 to January 2017 were selected as case group and control group. Erythrocyte sedimentation rate (ESR), interleukin6 (IL-6), interleukin8 (IL8), tumor necrosis factorα (TNF-α), total Blood highsensitivity Creactive protein (CRP) and serum procalcitonin (PCT) levels were detected. Flow cytometry was used to detect the expression levels of Wip1 and ROS in peripheral blood neutrophils of each group. The differences between the indicators were compared and the correlation between Wip1 and other indicators was analyzed. Results Compared with the control group, ESR, IL-6, IL-8, TNF-α, CRP and PCT in the case group were significantly increased (P＜0.01). The percentage of neutrophil Wip1+ in the control group and the case group was (13.88±0.79)% and (4.32±0.33)%. Compared with the control group, the percentage of Wip1+ in the case group was significantly lower (P=0.0001). The mean fluorescence intensity (MFI) of neutrophil ROS in the control group and the case group was (4.16±0.44)% and (1804±098)%. Compared with the control group, the ROS MFI in the case group was significantly increased (P＜00001). Wip1 was negatively correlated with IL-6 (r=0.3205, P=0.0188), CRP (r=0.3842, P=0.00244), PCT (r=0.3009, P=0.0195), ROS (r= 0.4039, P=0.0014). ROC curve analysis showed that the area under Wip1 curve in neutrophils was 0.9536(P＜0.0001). The diagnostic threshold of neutrophil Wip1 positive rate was 7.21%, sensitivity and specificity were 8833% and 9000%, respectively. Conclusion The decrease of Wip1 expression in peripheral blood neutrophils in children with bacterial pneumonia may be a potential diagnostic marker. The decrease of Wip1 expression may be related to the increase of autologous ROS and circulating IL-6, CRP and PCT.