The surgical conditions of the patients with CD4+ T lymphocytes higher than 200 cells/μL were better than those below 200 cells/μL. The incidence of postoperative adverse events in the experimental group (8%) was significantly lower than that in the control group (24%) with a difference of statistical significance (P < 0.05), which indicated that radical gastrectomy had different effects on the prognosis of AIDS patients complicated with gastric cancer with different immune levels. The gene discussed is CD4; the disease is gastric cancer.