Background: To evaluate the efficacy and influencing factors of programmed cell death protein 1 (PD-1) monoclonal antibody rechallenge therapy in advanced gastric cancer (GC). Methods: The clinical data of patients with advanced GC who were treated with PD-1 monoclonal antibody rechallenge in the Department of Gastroenterology, Henan Cancer Hospital from January 2020 to December 2021 were retrospectively collected. Results: A total of 60 patients with PD-1 monoclonal antibody rechallenge therapy were collected; the median follow-up time was 12.2 months. The median progression-free survival (PFS₂) of PD-1 monoclonal antibody rechallenge therapy was 2.9 months, and the objective response rate (ORR) was 16.7%, and the disease control rate (DCR) was 55.0%. The median PFS₂ of the same PD-1 monoclonal antibody for the first and second versus different PD-1 monoclonal antibody rechallenge treatment was (3.5 months vs. 1.9 months, P=0.006). The median PFS₂ of positive PD-L1 expression in rechallenge therapy was 3.4 months, ORR was 22.7%, and DCR was 63.6%; the median PFS₂ was 4.5 months, ORR was 27.3%, and DCR was 54.5% in patients with median PFS₁≥6 months. Multivariate analysis showed that peritoneal metastasis was independently associated with PD-1 monoclonal antibody rechallenge with median PFS₂ (P=0.034, HR=2.327, 95%CI 1.066-5.082). The incidence of adverse reactions in grade 1-2 and grade 3-4 of PD-1 monoclonal antibody rechallenge therapy was 83.3%, and 35.0%, respectively. and the safety was controllable. Conclusions: Rechallenge therapy with PD-1 monoclonal antibody is a feasible treatment in advanced GC, but the screening of suitable population for rechallenge therapy still needs prospective data analysis and verification.