Objective:Taken 16HBE human bronchial epithelial cell line as the research object, the effects of Qixian Decoction extract on inhibiting airway epithelial-mesenchymal transition(EMT)in asthma are investigated in vitro. MethodsThe 16HBE cells were intervened by H,2,O,2, and Qixian Decoction extract at different concentrations for different time to observe the cell morphology changes. CCK-8 assay was used to detect the effect of H,2,O,2, on the viability of 16HBE cells. RT-PCR was used to detect the gene expression levels of E-cadherin and α-SMA. The protein expression levels of E-cadherin and α-SMA were detected by Western blot. The protein expression levels and protein localization of E-cadherin and α-SMA were detected by immunofluorescence.  Results:The morphology of cells showed the changes of EMT after H,2,O,2, treatment, and the extract of Qixian Decoction reversed the EMT changes. The results of CCK-8 assay showed that the survival rate of airway epithelial cells was decreased with the increasing concentration of H,2,O,2, (P,<,0.01). The extract of Qixian Decoction reduced the damage of airway epithelial cells induced by H,2,O,2, (P,<,0.01). The results of RT-PCR showed that the level of E-cadherin mRNA in airway epithelial cells was significantly decreased after H,2,O,2, stimulation (P,<,0.01), and the level of α-SMA mRNA was increased (P,<,0.05). The extract of Qixian Decoction reversed the decreased level of E-cadherin transcription induced by H,2,O,2, (P,<,0.05), as well as the increased expression of α-SMA mRNA induced by H,2,O,2, (P,<,0.05). The results of Western blot and immunofluorescence showed that the protein expression levels of E-cadherin and α-SMA were consistent with the gene expression levels (P,<,0.05).  Conclusion:Qixian Decoction can reduce the airway epithelial cell damage and airway epithelial-mesenchymal transition induced by oxidative stress.