〔Abstract〕 Objective To explore the frontal EEG characteristics of elderly patients with postoperative delirium(POD) after spinal surgery under conscious and general anesthesia. Methods The inclusion criteria were patients aged≥65 years who underwent elective spinal surgery.POD was evaluated using The Confusion Assessment Method(CAM) 1-7 days after surgery.Patients were divided into two groups based on whether POD occurred: Postoperative Delirium Group(POD group) and Non Postoperative Delirium Group(Non POD group).The raw EEG data of two groups of patients in the EEG monitoring instrument were extracted, and the data of two time periods of wakefulness and anesthesia were intercepted for spectral analysis.The EEG data that did not meet the requirements were excluded, and ultimately 80 patients were included, including 32 in the POD group and 48 in the Non-POD group. Results Compared with the Non-POD group, patients in the POD group were found to be under anesthesia the power of θ、α、β waves(5-18 Hz) significantly decreased, the peak α frequency of the wave was slower(P=0.038),the peak power of α(P<0.001) and the total power were lower(P<0.001).Comparing the EEG changes between two groups from wakefulness to anesthesia, the study found that the increase of α power in POD group was not significant. Conclusion The characteristic electroencephalograms associated with POD in elderly patients during the perioperative period can help anesthesiologists to identify high-risk patients with POD in the early.