Abstract： Objective:To investigate the effects of intraoperative cerebral oxygen saturation on early postoperative cognitive dysfunction in elderly patients with intrathecal anesthesia.Methods:Select 64 elderly patients over 60 years of age undergoing elective surgery under ASA Ⅰ-Ⅲspinal anesthesia; 64 patients were randomly divided into intervention group and non-intervention group according to whether or not to take intervention measures on intraoperative cerebral oxygen saturation (rSO 2) Degree, 32 cases in each group. In the intervention group, intervention measures such as arousal were taken during the operation to keep the rSO 2 value above 89% of the basic value and the absolute value above 50; in the non-intervention group, only monitored cerebral oxygen saturation during the operation without intervention. On the 1st and 7th day after the operation, the composite Z-score recommended by ISPOCD was used to assess the occurrence of postoperative cognitive dysfunction in patients. Results:In the intervention group, the cerebral oxygen saturation did not decrease by more than 11%, and in the non-intervention group, the cerebral oxygen saturation of 26 patients decreased, and 10 of them declined by more than 11% ( P<0.05) . At 1st and 7th days after operation, the incidence of POCD in the intervention group was lower than that in the non-intervention group ( P<0.05) . Conclusion:Timely and moderate intervention of cerebral oxygen saturation during perioperative period can improve postoperative cognitive function and reduce the incidence of early postoperative cognitive dysfunction.