Abstract: Preoperative anxiety in children is a common psychological stress response during the perioperative period, which can significantly increase the risks of difficulties in general anesthesia induction, post-operative pain intensity, delayed recovery, and long-term neurobehavioral abnormalities. Dexmedetomidine, a highly selective α₂-adrenergic receptor agonist, exerts dose-dependent anxiolytic, sedative, and analgesic effects by acting on the central locus coeruleus, with minimal respiratory depression. It has become an important pharmacological intervention for preventing preoperative anxiety in pediatric perioperative management. This article systematically reviewed the neuropharma-cological mechanisms by which dexmedetomidine regulates anxiety and, based on existing clinical evidence, compares the pharmacokinetic characteristics, onset time, bioavailabilities, and applicable scenarios of its five commonly used administration routes in children, aiming to provide evidence-based references for optimizing the rational use of dexmedetomidine in pediatric preoperative sedation.