To explore the effect of atractylenolide Ⅱ(AT-Ⅱ) on the polarization of M2 macrophages and the migration of A549 cells,and to analyze its potential mechanism.THP-1 cells were induced into M0 macrophages using PMA,and then IL-4 and IL-13 were added to continue inducing M0 macrophages into M2 macrophages.M2 macrophages were co-cultured with A549 cells in Transwell chambers and treated with 0,2.5,5 μmol/L AT-Ⅱ.MTT assay was used to determine the effect of AT-Ⅱ on the viability of A549 cells under co-culture condition;Real-time PCR was used to detect the mRNA expression level of Arg-1;ELISA was used to detect TNF-α,IL-1β content in co-culture system;WB was used to detect the protein expression levels of TLR4,p-p65,NF-κB (p65),PDL1;Scratch experiment was used to detect the migration ability of A549 cells.The results showed that under co-culture condition,compared with the control group,the activity of A549 cells in the experimental group decreased,2.5 μmol/L group (P>0.05),5 μmol/L group (P<0.01);The mRNA expression level of M2 macrophage specific gene Arg-1 was significantly reduced (P<0.01);The content of M1 macrophage associated inflammatory factor TNF-α,IL-1β increased,but did not constitute a significant difference (P>0.05);The expression levels of TLR4,p-p65 and NF-κB (p65) proteins related to the TLR4/NF-κB signaling pathway decreased in A549 cells (P<0.01);The expression of PDL1 protein in A549 cells significantly decreased (P<0.01),and the ability of A549 cells migration decreased.These results indicate that AT-Ⅱ can reverse the polarization of M2 macrophages,inhibit NF-κB signaling pathway in A549 cells and reduce the expression level of PDL1,thus inhibiting the migration of lung cancer cells.