Abstract： Objective： To observe the effect of the combination use of saikosaponin and programmed death receptor 1/programmed death ligand 1 （PD-1/PD-L1） inhibitor on proliferation， migration and invasion of gastric cancer cells and phosphatidylinositol 3-kinase/serine/threonine protein kinase（ PI3K/AKT） signaling pathway. Methods： Human gastric cancer cells（ BGC-803） were taken to culture in PD-1/PD-L1 inhibitor medium（ PD-1/PD-L1 inhibitor group）， saikosaponin medium （saikosaponin group）， and PD-1/PD-L1 inhibitor combined with saikosaponin medium （combination group）， and BGC-803 cells in the control group were cultured in serum-free medium. The viability of gastric cancer cells was detected； the proliferation rate， apoptosis rate， migration rate， invasion rate， levels of apoptosis-related proteins [Bcl-2-associated X protein （Bax），B-cell lymphoma-2 （Bcl-2），Caspase3 and Caspase8] and PI3K/AKT expression levels were compared among the four groups. Results：Saikosaponin could inhibit the growth of gastric cancer cells in a dose-dependent manner. The IC50 of saikosaponin on gastric cancer cells was 12.50 μg/mL. The proliferation rates， invasion rates， migration rates and the relative expression levels of Bcl-2， PI3K， p-PI3K， AKT and p-AKT in the PD-1/PD-L1 inhibitor group， the saikosaponin group and the combination group were reduced when compared with those in the control group （P＜0.05），and the apoptosis rates and the relative expression levels of Bax， Caspase3 and Caspase8 were elevated （P＜0.05）. The proliferation rates， invasion rates， migration rates and the relative expression levels of Bcl-2， PI3K， p-PI3K， AKT and p-AKT in the PD-1/PD-L1 inhibitor group and the combination group were decreased when compared with those in the saikosaponin group （P＜ 0.05），and the apoptosis rates and the relative expression levels of Bax，Caspase3 and Caspase8 were increased （P＜ 0.05）. The proliferation rates， invasion rates， migration rates and the relative expression levels of Bcl-2， PI3K，p- PI3K，AKT and p-AKT in the combination group were reduced when compared with those in the PD-1/PD-L1 inhibitor group （P＜0.05）， and the apoptosis rates and the relative expression levels of Bax， Caspase3 and Caspase8 were elevated （P＜0.05）. Conclusion：The intervention of saikosaponin combined with PD-1/PD-L1 inhibitor can inhibit the proliferation， migration， and invasion of gastric cancer cells and the activation of PI3K/AKT signaling pathway， and promote the apoptosis of gastric cancer cells.