Background　Dexmedetomidine(Dex) is a potent selective agonist of α2 adrenoceptor. It has been widely used in clinical anesthesia and intensive postoperative care. However, the application of Dex in children is not as common as in adults because the safety and effectiveness in pediatric cardiac surgery need further evaluations.　Objective　To review the recent studies in applying Dex in pediatric cardiac surgery to provide guidance for clinical use of Dex in children.　Content　Adults gain benefits from perioperative use of Dex, such as stabilization of hemodynamics, control of stress reactions, reduction of consumption of opioids and other anesthetics, and protection of organs, etc. Children, especially neonates, differ from adults in pharmacokinetics, hemodynamics, blood oxygen balance, cardiac function, and maturation of the central nervous system. Cautions need to be taken to administer Dex in pediatric cardiac surgery utilizing either catheterization or direct vision procedure.　Trend　Large sampled, multiple contered, and randomized clinical investigations are warranted to further assess the safety and effectiveness of Dex in pediatric cardiac surgery．