To investigate the regulatory mechanism of honokiol(HNK) on the biological activity of lung cancer cells(A549 cells).Methods:A549 cells in the logarithmic phase were treated with 0，10，20，40，and 80 μmol/L HNK for 0，24，and 48 h.The MTT method was adopted to measure cell proliferation and optimal HNK concentration and treatment time.The cell cloning formation test was performed to assess the effect of HNK on A549 cell proliferation ability，while the scratch test and cell migration and invasion tests were conducted to evaluate the influence of HNK on A549 cell migration and invasion.Different fluorescent staining methods were employed to measure intracellular reactive oxygen species(ROS) content，autophagy，mitochondrial membrane potential changes，and apoptosis.Western blotting(WB) was utilized to detect the expression of related proteins.Results:Based on the MTT method，the cell inhibition rate curve was obtained，and HNK concentrations of 40 and 80 μmol/L with a treatment duration of 48 h were selected for subsequent experiments.Compared with the 0 μmol/L group，40 and 80 μmol/L HNK can significantly inhibit A549 cell proliferation，cloning formation，migration，and invasion，while increasing intracellular ROS levels，and promoting autophagy and apoptosis in a concentration-dependent manner.Compared with the 0 μmol/L group，40 and 80 μmol/L HNK downregulated the expression of B-cell lymphoma-2(Bcl-2)，ubiquitin-binding protein(p62)，vimentin，neural cadherin(N-cadherin)，nuclear factor E2-related factor 2(Nrf2)，and heme oxygenase-1(HO-1) proteins，while upregulating the expression of Beclin1，microtubule-associated protein 1 light chain 3(LC3)，and E-cadherin(P<0.05).Conclusion:HNK can both inhibit the proliferation，migration，and epithelial-mesenchymal transition(EMT) of lung cancer cells and promote autophagy and apoptosis.Its mechanism may be associated with the suppression of the Nrf2/HO-1 signaling pathway.