Perioperative neurocognitive disorders (PND) are one of the most common postoperative complications in elderly patients undergoing surgery, and a hot issue of common concern for anaesthesia, psychiatry and geriatric specialties. A number of studies have now confirmed the existence of an important interaction between gut flora and the brain, known as the gut-brain axis. Intestinal flora plays a central role in the gut-brain axis and its homeostasis has an important impact on neurocognitive function. This article reviews the close relationship between intestinal flora disorders and PND, the disruption of intestinal flora homeostasis during surgery and anaesthesia, and the intervention of PND by regulating intestinal flora, based on domestic and international research progress, with a view to providing reference for clinical work and scientific research