Postoperative delirium (POD) is an acute cognitive disorder marked by attention deficits, fluctuating symptoms, and significant cognitive impairment. These features are closely associated with adverse outcomes, including increased mortality, prolonged hospitalization, long-term cognitive deficits, and elevated healthcare costs. Brain functional connectivity studies focus on understanding complex neuronal interactions and interregional communi cation within the brain. This article explores the association between POD and brain functional connectivity. It be gins by summarizing the prominent features of POD as a common postoperative complication and its substantial impact on patient health, highlighting current limitations in understanding the pathophysiological mechanisms. The article then investigates the relationship between functional connectivity and cognitive function, emphasizing the role of advanced monitoring techniques, including Electroencephalography and Functional Magnetic Reso nance Imaging. The advantages and limitations of these technologies in studying brain connectivity are discussed. Additionally, the article focuses on the posterior cingulate cortex and Default Mode Network, examining their roles in the development of POD and their potential connections to its pathogenesis. Finally, the application of graph theory in connectivity analysis is introduced, offering new insights into POD’s pathogenesis. Based on current evidence, the article provides an outlook on future research directions and potential challenges. This study par ticularly emphasizes the impact of perioperative factors, such as anesthesia and postoperative inflammation, on brain functional connectivity. These changes may trigger POD by disrupting connectivity within the Default Mode Network and other key neural networks. By investigating the changes in brain functional connectivity patterns in patients undergoing different types of surgeries, this study further reveals the contribution of perioperative factors to the pathophysiological mechanisms of POD.