Objective To evaluate the effect of dexmedetomidine（Dex） on Phosphatidylinositol 3 kinase （PI3K） and protein kinase B（PKB/Akt） concentration during perioperative period in patients with meningioma.　Methods　Forty-five ASAⅡor Ⅲ patients with meningioma 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 Akt and PI3K respectively at the time before induction（T1）， removal of tumor（T2）， extubation（T3） and 24 h after operation（T4）. Blood samples were also collected from radial artery and jugular venous bulb for blood gas analysis to calculate the arterial oxygen content（CaO2），cerebral arterial venous oxygen content difference cerebral arterial venous oxygen content difference（Da-jvO2） and cerebral extraction of oxygen（CEO2）.　Results　Compared with T1， the serum concentration of Akt and PI3K and CEO2 significantly increased at T2-T4 in the all groups（P<0.05）. There was significant difference between group C and group D2 in the concentration of PI3K and Akt at T2-T4（P<0.05）， PI3K in group C were［（5.9±0.5），（6.8±0.6），（8.2±0.5） μg/L］， while that of group D2 were［（5.5±0.4），（6.3±0.5），（7.1±0.6） μg/L］respectively at T2-T4. Akt in serum in group C were［（0.401±0.032），（0.482±0.050），（0.593±0.058） μg/L］， while that of group D2 were［（0.351±0.024），（0.414±0.023），（0.472±0.033） μg/L］ respectively at T2-T4. There was significant difference among the three groups in CEO2 at T2-T3（P<0．05）， 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 patients with meningioma. The mechanism may be associated with lowering plasma PI3K and Akt and cerebral oxygen uptake rate.