Objective To explore the clinical effect of oxaliplatin combined with tegio in the treatment of elderly patients with gastric cancer and its influence on immune function and serum tumor markers. Methods? A total of 86 elderly patients with gastric cancer from January 2019 to May 2020 in Affiliated Cancer Hospital of Shanxi Medical University（Shanxi Cancer Hospital）were selected and divided into two groups（43 patients）according to the random number table method.The control group was treated with FOLFOX6 chemotherapy and the study group with oxaliplatin + tegio chemotherapy.The two chemotherapy regimens were compared in terms of clinical efficacy，patients' immune function，serum tumor marker levels，and adverse effect rates. Results? After treatment the total effective rate of the treatment group was significantly higher than that of the control group（69.77% vs. 48.84%，P＜0.05），the study group had higher CD3+，CD4+，CD4+/CD8+ levels than the control group（P ＜0.05），and the serum tumor marker levels CEA，CA242，CA199 levels were lower（P＜0.05）. And the incidence of nausea and vomiting in the treatment group was lower than that of the control group（P＜0.05）. Conclusion? Oxaliplatin + tegio chemotherapy in elderly patients with gastric cancer can achieve significant clinical efficacy，help to enhance the immune function of patients，reduce the level of serum tumor markers，reduce drug toxicity and side effects，and improve patient tolerance.