Objective To study the effect and safety of dexmedetomidine on the intraoperative fentanyl requirements and cerebral hemodynamics in patients undergoing intracranial tumor surgery.Methods 62 patients scheduled for intracranial tumor surgery were selected and divided into observe group (31 cases) and control group(31 cases).Dexmedetomidine (0.5 μg/kg) was loaded in observe group,and followed by a continuous infusion of a rate of 1.0pμg · kg-1 · h-1 half an hour later.Saline was infused in the same time and the same way in control group.Dose of anesthetic and change of cerebral hemodynamics were recorded and compared.Results The mean heart rate and mean arterial blood pressure were lower in observe group than the underlying value when inducing anesthesia and during the operation (all P ＜ 0.05),while that happened after operation starting 60 minutes later in control group(all P ＜0.05).The mean heart rate and mean arterial blood pressure were lower in observe group those that in control group (all P ＜ 0.05).Dose of fentanyl and end-tidal sevoflurane concentration were lower in observe group(all P ＜ 0.05).Conclusion Dexmedetomidine used for cerebral hemodynamics stabiliby in intracranial tumor surgery has obvious curative effect and good safety.And it could decrease the dose of anesthetics and anesthesia adjuvant.