Objective:To explore the influence of combination of sintilimab and platinum-based chemotherapy on immune inde-xes and survival cycle in patients with advanced gastric cancer(AGC).Methods:82 patients with AGC were included and divided into chemotherapy group(n=41,platinum therapy)and combined group(n=41,sintilimab+platinum therapy)according to different treatment regimens.21 days was one cycle,both groups were treated for 3 cycles,followed up for 1 year.The immune indicators[CD3+T cell,CD4+T cell,CD8+T cell and CD4+/CD8+T cell levels]and angiogenesis indexes[endostatin(ES),angiopoietin-2(Ang-2),vascular endothelial growth factor(VEGF)]before and after treatment,clinical efficacy and incidence rates of adverse reactions were compared between the two groups.Kaplan Merier was used to analyze the 1-year survival status of the two groups.Results:After treatment,compared with the chemotherapy group,the levels of CD3+,CD4+,CD4+/CD8+,ES,total effective rate and 1-year survival rate in the combined group were higher(P＜0.05)while the levels of CD8+,Ang-2 and VEGF were lower(P＜0.05).There were no statistical differences in adverse reactions between groups(P＞0.05).Conclusion:The application of sintilimab combined with plati-num-based chemotherapy for patients with AGC can reduce the influence of chemotherapy on immune function,inhibit the tumor angio-genesis,and enhance the clinical efficacy and survival rate,and it has safety.