To explore the molecular mechanism by which Weichang'an inhibits the invasion and metastasis of gastric cancer through the chemokine-like factor(CKLF)-like MARVEL transmembrane domain-containing protein 6(CMTM6)/programmed death ligand 1(PD-L1) axis.Methods:Human gastric cancer cell lines MKN45 and MGC803 were used.The cell proliferation was assessed by a cell proliferation assay to determine the inhibitory effect of Weichang'an on cell growth.The inhibitory effect of Weichang'an on cell migration and invasion were measured using scratch assay and invasion assay，respectively.The mRNA levels of CMTM6 and PD-L1 in each group were quantified by real-time fluorescence quantitative PCR.Immunofluorescence staining was used to detect the protein fluorescence intensity of CMTM6 and PD-L1.Protein levels of MMP2，MMP9，E-cadherin，N-cadherin，vimentin，CMTM6，and PD-L1 were measured using Western blot.Results:Weichang'an significantly inhibited the proliferation，migration，and invasion of human gastric cancer cells(MKN45 and MGC803).It decreased the expression levels of MMP2，MMP9，N-cadherin，and vimentin，while increasing the expression of E-cadherin.Additionally，it reduced both the protein and mRNA expression levels of CMTM6 and PD-L1.Conclusion:Weichang'an can inhibit the migration，invasion，and epithelial-mesenchymal transition(EMT) of human gastric cancer cells，and its mechanism may be related to the regulation of the CMTM6/PD-L1 axis.