There are many factors that make elderly patients prone to POD. On the basis of these factors, surgery and anesthesia can increase the incidence of POD in elderly patients. Deep depth of intraoperative anesthesia and persistent hypotension may increase the risk of POD occurrence in elderly patients. So far, no specific POD prevention method has been found. In recent years, a large number of studies on POD have brought forward more new views on its pathogenesis, prevention and treatment. There is insufficient evidence to recommend specific anesthetic agents and dosages to reduce the risk of POD in elderly patients, and only low-quality evidence to recommend propofol. At present, it is considered that the best way to reduce postoperative delirium is perioperative risk management, to evaluate high-risk patients or patients undergoing high-risk surgery as extensive as possible, and to quantify their risk of postoperative delirium. Effective measures include depth management of anesthesia, multi-modal analgesia management, and optimization of drug intervention. Ciprofol is a class 1 innovative drug independently developed by China and with global independent intellectual property rights. Ciprofol has been widely used in anesthesiology and critical care medicine. The pre-market phase I-III and post-market data showed that during the induction and maintenance of general anesthesia, Ciprofol had less impact on hemodynamics and more stable anesthesia depth than propofol. Relevant studies have shown that Ciprofol can reduce the risk of hypotension, and can provide better brain oxygenation and more stable intraoperative hemodynamics than propofol. At present, the influence of different sedative drugs on POD incidence in elderly patients remains to be studied. Therefore, we will apply Ciprofol or propofol in elderly patients undergoing thoracic surgery to observe their influence on POD incidence and provide reference for clinical use.