Objective To explore the effects of dioscin (Dio) on airway inflammation and microRNA-155 (miR-155)/cyclooxygenase 2 (COX-2)/prostaglandin E2 (PGE2) pathways in asthmatic mice. Methods Seventy mice were randomly divided into control group, model group, inhibitor negative control group (inhibitor-NC group), miR-155 inhibitor group, and Dio group, Dio+miR-155 mimic negative control group (Dio+mimic-NC group), Dio+miR-155 mimic group, with 10 mice in each group. Using house dust mite to induce the preparation of asthma mouse models; enzyme linked immunosorbent assay was used to detect the levels of PGE2, tumor necrosis factor α (TNF-α), cysteyl leukotrienes (CysLTs), cysteyl leukotriene receptor 1 (CysLTR1) and interleukin (IL)-4, IL-5, IL-13 in mouse bronchoalveolar lavage fluid (BALF); hematoxylin-eosin and periodic acid-Schiff staining were used to observe the infiltration of inflammatory cells around the airway and the secretion of mucus by goblet cells; quantitative real-time PCR was used to detect the expression levels of miR-155 and COX-2 mRNA in mouse lung tissue; Western blot was used detect the expression of COX-2 protein in mouse lung tissue. Results MiR-155 inhibitor and Dio could reduce the levels of PGE2, TNF-α, CysLTs, CysLTR1 and IL-4, IL-5, IL-13 in BALF of asthmatic mice, reduce lung tissue inflammatory cell infiltration and goblet cell mucus secretion, and reduce lung tissue miR-155, COX-2 mRNA and protein expression; and miR-155 mimic could significantly weaken the anti-asthma effect of Dio. Conclusion The anti-asthma effect of Dio may be related to the inhibition of miR-155/COX-2/PGE2 pathway to reduce airway inflammation in asthmatic mice.