Objective To investigate expression of TREM-1/DAP12 protein in children with respiratory syncytial virus (RSV) bronchiolitis as well as potential relationship between this pathway and inflammation. Methods From January 2017 to January 2019, children with RSV bronchiolitis in Guangan People's Hospital of Sichuan Province were selected as case group (they were divided into mild group and severe group), healthy children who had physical examination during the same period were selected as control group, levels of inflammatory factors in serum and expression of TREM-1 and DAP12 in peripheral blood mononuclear cells (PBMCs) were detected. In vitro cell model of human bronchial epithelial (NHBE) cells infected by RSV was constructed, NHBE cells were divided into control group, RSV-infected group, RSV+siRNA-Control group and RSV+siRNA-TREM-1 group. Expression of TREM-1 and DAP12 in cells as well as level of inflammatory factors in supernatant were detected. Results Serum levels of inflammatory factors such as interleukin-1β(IL-1β) and expression levels of TREM-1 and DAP12 in PBMCs in children in mild and severe groups were both higher than those in control group, and severe group were higher than mild group (all P<0.05). The expression of TREM-1 and DAP12 in RSV-infected group and RSV+siRNA-Control group were both higher than control group and RSV+siRNA-TREM-1 group (both P<0.05). Levels of inflammatory factors in supernatant of RSV+siRNA-TREM-1 group were all lower RSV-infected group and RSV+siRNA- Control group (all P<0.05). Conclusion TREM-1/DAP12 signaling pathway is highly expressed in children with RSV bronchiolitis. RSV induces overexpression of TREM-1 in NHBE cells, and silencing TREM-1 can down-regulate DAP12 expression and inhibit the secretion of inflammatory factors.