One hundred fourteen elderly patients undergoing elective hip joint surgery were randomized to receive ciprofol-based anaesthesia (0.3 mg/kg induction; n=57) or propofol-based anaesthesia (1.5 mg/kg induction; n=57). The primary outcome of interest was the incidence of postoperative delirium (POD) within the first 3 postoperative days, assessed with the 3D-CAM on postoperative days 1 and 3. Secondary outcomes of interest included intraoperative haemodynamics (MAP, HR), depth of anaesthesia (Narcotrend index), need for vasoactive drugs, anaesthesia induction characteristics (time and rescue doses), adverse events (myoclonus, injection pain, PONV), and perioperative serum Silent information regulator factor 3(SIRT3) levels with exploratory ROC analysis for POD prediction. Outcomes were assessed intraoperatively and on postoperative days 1 and 3. Overall, the results of the study revealed that ciprofol was associated with a significantly lower overall incidence of POD, more stable circulatory parameters with reduced vasopressor use, less injection pain but more myoclonus, and higher early postoperative SIRT3 levels, with SIRT3 on day 1 showing good diagnostic performance for POD. These findings suggest that ciprofol may be a preferable induction agent to reduce delirium risk in elderly hip arthroplasty patients, and that postoperative SIRT3 could serve as a candidate biomarker for POD.