The present study is a multicenter， randomized controlled clinical trial, which plans to enroll 450 diabetic patients aged more than 60 years. The participants will be randomly assigned in a 1:1 ratio and will receive either propofol or sevoflurane for intraoperative anesthesia maintenance to evaluate the impact of these two anesthetic drugs on postoperative delirium. The aim of our study is to explore whether the use of propofol for anesthesia maintenance in elderly diabetic patients undergoing elective non-cardiac major surgery can reduce the incidence of postoperative delirium. Exploratory analysis was conducted to observe the differences in perioperative levels of blood glucose, serum insulin, inflammatory factors (IL-6, IL-1β, TNF-α), neuroinjury markers (S-100β protein, neuron-specific enolase) between the two groups. This study will provide new perspectives for improving perioperative management in elderly diabetic patients and optimizing anesthesia management strategies to reduce the risk of postoperative delirium.