Objective To study the protective effect of aerosolized glycyrrhizic acid (GA) on Bleomycininduced pulmonary fibrosis in mice and the mechanism. Methods A total of 90 male Kunming mice (SPF grade) were randomly divided into 6 groups: control group, model group, GA250 group (IA), GA12 group, GA24 group and Budesonide (AI) group. The model group and treatment groups were given intratracheal instillation of 5 mg/kg Bleomycin solution to establish pulmonary fibrosis model in mice. After 24 hours, the GA250 group was administered with GA solution at the dose of 250 mg/kg, the GA12 and GA24 groups were given inhalation of 4 ml GA solution at the dose of 12 mg/ml and 24 mg/ml respectively, the Budesonide group was given aerosol inhalation of 4 ml Budesonide suspension at the dose of 1 mg/4 ml, the mice in the control group and the model group inhaled the same amount of saline. Atomization treatment was given once a day for 21 days. On the 7th, 14th and 21st day, 5 mice were randomly sacrificed in each group. HE staining and Masson staining were used to evaluate the inflammation and fibrosis of the lung tissues; the level of HYP in serum and the levels of IL-6 and TGF-β1 in the lung tissues were measured to evaluate the levels of inflammatory factors and collagen; the expression levels of IL-6, IL-17, p-Smad2 and TGF-β1 proteins were detected by Western blot. Results The expression of IL-16 increased on the 7th day after modeling, then gradually decreased; and the expression of IL-17 increased gradually, and the expressions of TGF-β1 and p-Smad2 also gradually increased. GA12 and GA24 significantly decreased the levels of IL-17, TGF-β1 and p-Smad2, and the results were better than those of the Budesonide and GA250 groups. Conclusions Aerosol inhalation of glycyrrhizic acid alleviates Bleomycin-induced pulmonary fibrosis in mice by IL-17/TGF-β/Smads pathway.