Ｏｂｊｅｃｔｉｖｅ　To evaluate the effect of dexmedetomidine（Dex） on glial fibrillary acidic protein（GFAP） and brain typeisoenzyme of creatine phosphokinase（CK-BB） concentration during perioperative period in patients with meningioma， and to evaluate the cerebral protection function of Dex during surgery.　Methods　Forty-five ASAⅡor Ⅲ patients with meningioma aged 45 y-65 y weighing 55 kg-65 kg scheduled for elective intracranial tumor recection were randomly divided into 3 groups（n=15）： control group （group C）, low-dose Dex group （0.2 μg·kg-1·h-1，group D1）, high dose Dex group 0.5 μg·kg-1·h-1（group D2）. Dex was intravenously infused 10 min before induction at the dose of 1 μg/kg， followed by constant speed infusion at 0.2 μg·kg-1·h-1 and 0.5 μg·kg-1·h-1 in group D1 and D2 respectively until 30 min before the end of the operation. Group C received the same volume of saline. Bispectral index （BIS） was maintained at 40-49. Venous blood samples were taken for determination of serum concentrations of GFAP and CK-BB respectively before induction （T1）， at the time of dislodging tumor （T2）， during extubating trachea （T3） and 24 h after operation（T4）. Blood samples were also collected from left radial artery and right jugular venous bulb for blood gas analysis to calculate the arterial oxygen content（CaO2）， cerebral arterial venous oxygen content difference（Da-jvＯ2）， cerebral extraction of oxygen（CEO2）.　Results　Compared with T1， the concentration of GFAP and CK-BB in serum and CEO2 significantly increased at T2-T4 in all of the groups（P<0.05）. There was significant difference between group C and group D2 in the concentration of GFAP and CK-BB in serum at T2-T4（P<0.05）， The numerical values of GFAP in serum in group C were［ （0.72±0.05），（0.80±0.05），（0.90±0.05） μg/L］， while that of group D2 were ［（0.78±0.06），（0.88±0.07），（1.17±0.19） μg/L］， respectively at T2-T4. The numerical values of CK-BB in serum in group C were［（30.6±2.6），（33.2±3.4），（36.1±2.8） U/L］， while that of group D2 were ［（19.3±1.8），（21.1±2.4），（23.5±2.8） U/L］， respectively at T2-T4. There was significant diferenee in the three groups about CEO2 at T2-T3（P<0.05）， The numerical values of CEO2 in group C were ［（0.36±0.03）%，（0.34±0.03）%］， while that of group D1 were ［（0.33±0.04）%，（0.30±0.04）%］， and group D2 were ［（0.32±0.04）%，（0.26±0.04）%］， respectively at T2-T3.　Conclusions　Intraoperative infusion of dexmedetomidine may play a protective effect on（role in） patients with meningioma， The mechanism may be associated with lowering plasma GFAP and CK-BB concentrations and cerebral oxygen uptake rate.