The aim of this study was to investigate the influence of epithelial-mesenchymal transition (EMT) occurring in gastric carcinoma cells and the involvement of programmed death ligand 1 (PD-L1) expression in tumor cells that undergo EMT. The mechanisms underlying PD-L1 expression during EMT in gastric carcinoma cells were also explored.The capacities of migration and invasion were tested by cell scratch-wound assay and transwell chamber assay. PD-L1 expression by SGC7901 cell line and related mechanism were measured by Western blot and QRT-PCR.Treating with TGF-β1 promotes the motility of SGC7901 and PD-L1 expression in vitro, while activating the NF-κB signal pathway.EMT increases the capacities of migration and invasion in gastric cancer cells, which resulted in up-regulation of PD-L1 expression via a mechanism that is dependent on NF-κB activation.