Objective To investigate the effect of BIS-guided closed-loop target-controlled infusion on perioperative Th1/Th2 balance in elderly patients undergoing laparoscopic radical gastrectomy under different anesthesia and sedation depths. Methods We applied random number table method to divide 73 elderly patients undergoing elective laparoscopic radical gastrectomy into BIS closed-loop target-controlled infusion group with BIS value of 55(group H, n=36) and BIS value of 45(group L, n=37).Intravenous blood samples were collected immediately before surgery (T1), 2h after surgery (T2), 24h after surgery (T3) and 72h after surgery (T4).IL-2, IL-4, IL-6, IL-10, TNF-α and IFN-γ were determined by flow cytometry microsphere array.We compared operation duration, postoperative PACU stay time and postoperative hospitalization time between two groups. Results Compared with T1, IL-6 and IL-10 concentration in group H at T2, T3 and T4 significantly increased (P < 0.05), IL-4 and TNF-α in group H at T4 were significantly increased (P < 0.05), IL-2 and IFN-γ in group H at T2 and T4 were significantly increased (P < 0.05), the concentration of IL-6 and IL-10 in group L at T2, T3 and T4 were increased (P < 0.05), IL-2 in group L at T4 was decreased (P < 0.05), and IFN-γ/IL-6 in two groups were decreased at T2, T3 and T4(P < 0.05).Compared with group L, IL-6 and IL-10 in group H were significantly increased at T2(P < 0.05), IFN-γ/IL-6 in group H was significantly decreased (P < 0.05), IL-2 and IL-10 in group H were significantly increased at T4(P < 0.05).Operation duration, postoperative PACU stay time and postoperative hospitalization time had no statistical significance between two groups (P > 0.05). Conclusion The anesthesia and sedation depth of BIS-guided closed-loop target-controlled infusion set at 45 is better than 55 in maintaining Th1/Th2 balance in elderly patients undergoing laparoscopic radical gastrectomy, but it has no obvious effect on long-term prognosis.