Objective:To observe the effect of D-pinitol on the expression of transforming growth factor-β1(TGF-β1) in a murine model of chronic asthma. Methods: Eighteen BALB/c mice were randomly divided into 3 groups,namely control group,OVA group and D-pinitol group. Pulmonary function was measured to evaluate the resistance of expiration 24 hours after the last OVA challenge,hematoxylin and eosin(HE) staining was used to assess the inflammatory cell infiltrates,and Masson’s trichrome to determine airway fibrosis. The expression of TGF-β1 mRNA in lung was measured by real-time PCR. The concentration of TGF-β1 in bronchoalveolar lavage fluid (BALF) was measured by enzyme-linked immunoabsorbent assay (ELISA). Results: All the parameters associated with airway inflammation,airway hyperresponsiveness (AHR) and remodeling were increased in the OVA group,and decreased by treatment of D-pinitol(P < 0.05). Treatment with D-pinitol significantly inhibited the levels of TGF-β1 in the lung tissue and in the BALF(P < 0.05). Conclusion: These data demonstrated that D-pinitol could suppress the progression of airway remodeling in a murine model of chronic asthma. Partly,the effect might be due to inhibition of the expression of TGF-β1.