Objective : To analyze the current status of anti-PD-1 combined with chemotherapy in advanced gastric cancer. Methods: The clinical data of 120 patients with advanced gastric cancer treated with chemotherapy or anti-PD-1 plus chemotherapy were retrospectively analyzed. The efficacy [measures include objective response rate(ORR), disease control rate(DCR), and progression-free survival(PFS)]and the occurrence of adverse reactions in patients was monitored. Univariate and multivariate Cox were used to analyze the relationship between clinicopathologic data [including age, gender, body mass index(BMI), differentiation degree, and related hematological indexes], specific treatment conditions and PFS, and to analyze the influence of treatment plan and line number on the curative effect. Results : The PFS of chemotherapy plus immunotherapy was significantly better than that of chemotherapy alone(P<0.05), and the median PFS of the two was 7.17 months(95%CI5.85-8.49) and 5.33 months(95%CI3.96-5.70), respectively. In the combination group, the overall ORR was 27.5% and DCR was 94.8%. In the chemotherapy group alone, the overall ORR was 9.7% and DCR was 69.4%.In the chemotherapy plus anti-PD-1 group, a high prognostic nutritional index(PNI) level also provided superior PFS in patients with a 47% reduction in the risk of progression versus a low PNI level [HR0.53(95%CI0.30-0.96);P<0.05]. The median PFS was 7.47 months(95%CI5.83-9.11) with a high PNI level versus 6.00 months(95%CI4.45-7.55) with a low PNI level. The overall incidence of adverse reactions of chemotherapy combined with anti-PD-1 was slightly higher than that of chemotherapy alone, and the incidence of adverse reactions of grade 3-4 was similar, within a controllable range, and could be improved after clinical treatment. Conclusion The efficacy of anti-PD-1 combined with chemotherapy in patients with advanced gastric cancer is better than that of chemotherapy, and the adverse reactions are controllable. In the chemotherapy plus anti-PD-1 group, patients with high PNI levels achieved a higher PFS.