ObjectiveTo investigate the impactsof different time-course electroacupuncture pretreatments on brain water content and blood-brain barrier permeability and assess their protecting effects on blood-brain barrier functionin cerebral ischemia rats. MethodClean-grade healthy male SD rats were randomly allocated to five groups (n=48): model control group, and one-day, three-day, seven-day and fifteen-day electroacupuncture pretreatment groups. A rat model of unilateral middle cerebral artery occlusion (MCAO) was made after electroacupuncture pretreatment was finished in various electroacupuncture groups. The water content of the brain and the amount of EB through blood brain barrier were measured at 12, 24 and 48 hrs after cerebral ischemia. ResultBoth brain water content and EB permeation amount were lower at 12 and 48 hrs than at 24 hrs after cerebral ischemia (P<0.05). There was a significant reducing effect on brain water content and EB permeation amount in the fifteen-day electroacupuncture pretreatment group at various time points after cerebral ischemia (P<0.05,P<0.01,P<0.001).Conclusion The blood-brain barrier is impaired most severely at 24 hrs of the three time points 12, 24 and 48 hrs after cerebral ischemia. Electroacupuncture pretreatment can produce a protecting effect on blood-brain barrier function in cerebral ischemia rats by markedly reducing cerebral edema and blood-brain barrier permeability.