Based on the airway IL-17/IL-23 inflammatory factor axis，to explore the protective mechanism of Ginsenoside Rg1 on lung injury in PM2.5 asthmatic rats.Methods:PM2.5 was isolated and sensitized by ovalbumin，and then PM2.5 was intratracheal instilled to establish PM2.5 asthmatic lung injury model.The levels of IL-17a，IL-6，IL-23 and TGF-β1 in serum and BALF were measured by ELISA.The expression of RORγt mRNA was detected by RT-PCR，and the lung tissue pathology and electron microscopy were analyzed.Results:The asthmatic rat model of PM2.5 was established successfully; The expression of IL-17a，IL-6，IL-23 and TGF-β1 in serum and BALF of asthmatic rats increased(P<0.01)，and the expression of RORγt mRNA in lung tissue increased(P<0.01); After PM2.5 intratracheal instillation，the contents of IL-17a，IL-6，IL-23 and TGF-β1 in serum and BALF of model group were further increased，and the expression of RORγt mRNA was further increased(P<0.01);After intervention with saponin Rg1，IL-17a，IL-6，IL-23，TGF-β1 in serum and BALF were decreased in a dose-dependent manner，and RORγt mRNA expression was down regulated.Conclusion:Ginsenoside Rg1 can improve airway inflammation and lung injury induced by PM2.5 in a concentration dependent manner.