Abstract: OBJECTIVE To investigate the effect and mechanism of Mahuang-Gancao couplet medicines (MG) on allergic asthma. METHODS The airway responsiveness was detected by non-invasive pulmonary function test. The pathological changes of lung tissue were observed by HE staining. The collagen deposition of lung tissue was observed by Masson staining. The eosinophil (EOS) count in blood was performed. IL-4， IL-5， IL-13， TGF-β1 and IgE were detected by ELISA assay. The expression of E-cadherin， N-cadherin， Vimentin， α-SMA and TGF-β1 were detected by immunohistochemistry. RESULTS MG significantly reduced airway hyperresponsiveness， inhibited the expression of IL-4， IL-5 and IL-13 in BALF and lung tissue， decreased the expression of serum IgE， and alleviated inflammation of lung tissue. MG inhibited the expression of TGF-β1 in lung tissue， increased the expression of E-cadherin and down-regulated the expression of N-cadherin， Vimentin and α-SMA. CONCLUSION MG can play a key role in the treatment of allergic asthma by inhibiting the bronchial epithelial-mesenchymal transition， thereby alleviating the inflammatory state of the airway and improving the airway remodeling of asthma.