An excellent recovery profile is critical for neurosurgical anesthesia. Rapid awakening, smooth blood pressure and heart rate (HR), a higher degree of coordination, painless or mild pain, as well as better tolerance to endotracheal intubation can avoid can increased intracranial pressure, elevated blood pressure and rapid HR caused by emergency choking, suffocation and agitation, and can reduce postoperative cerebral edema and the risk of bleeding. In addition, it is easy for surgeons to timely evaluate postoperative patients' neurologic function based on the excellent recovery from anesthesia. Up to now, there are many methods and drugs to improve the quality of recovery period, but each of them has some flaws. Dexmedetomidine, an emerging anesthetic adjuvant, exhibits a stable hemodynamic recovery period, and cannot affect evaluation of neurological function with both the sedative and analgesic effects. We propose the following hypotheses: (1) A small dose of dexmedetomidine can be intravenously injected into patients subjected to craniotomy under general anesthesia, in order to improve the recovery profiles and reduce the incidence of emergence agitation. (2) Dexmedetomidine can reduce postoperative pain.