Objective: Gastric cancer (GC) is one of the most important upper gastrointestinal malignancies worldwide. Anti-tumor effect of PD-1/PD-L1 inhibitor alone is insufficient, furthermore its combination chemotherapy provides a new direction. To analyze the effectiveness and safety of combination therapy of PD-1/PD-L1 inhibitor combined with CHEMO in regimens of advanced gastric carcinoma (GC). Chinese and English databases were searched to collect clinical randomized controlled trials (RCTs) of PD-1/PD-L1 inhibitors combined with CHEMO in therapy of advanced carcinoma GC/ gastroesophageal junction cancer (GEJC). Combined group ORR (OR=2.63, 95%CI: 1.47~4.68) and DCR (OR=2.42, 95%CI: 1.07~5.51) higher than the control group, FPS (HR=0.71, 95%CI: 0.65~0.77) and OS (HR=0.80, 95%CI: 0.73~0.86) showed a significantly better condition than control group. The occurrence rate of grade 3-5 untoward effects in the combination group showed a higher data than control group, OR=1.24 (95CI: 1.03, 1.49). PD-1/PD-L1 inhibitor combined with CHEMO can promote the treatment effect in advanced GC and build up the medical forecast of patients, but it can increase the incidence of serious adverse reactions.