Background　Dexmedetomidine(Dex), a potent selective agonist of alpha-2 adrenergic receptors, has sedative, analgesic, and anxiolytic properties. It has been widely used in clinical anaesthesia. Numerous studies revealed that Dex is a valuable anesthetic in cardiovascular surgeries.　Objective　To summarize the efficacy and safety of Dex in cardiovascular surgery, and to provide the knowledge for its clinical application.　Content　Dex is effective to maintain normal cardiovascular functions, including stabilizing hemodynamics, reversing arrhythmia, protecting myocardium, preventing postoperative delirium, and restricting inflammatory reactions.　Trend　Dex has particular advantages in the perioperative period of cardiovascular surgery, while further investigations should be conducted to assess indications of Dex and strategies to solve its adverse effects, before applying Dex as a routine drug in clinical practices.