Objective To investigate the protective effect of Codonopsis pilosula on ischemia and reperfusion-induced brain injury in Wistar rats and the mechanism of its action.Methods One hundred Wistar rats were divided randomly into 4 groups: Group A, sham-operated(SH); Group B, cerebral ischemia and reperfusion+NS(IR+NS); Group C, cerebral ischemia and reperfusion+Codonopsis pilosula (IR+Codo.); Group D, cerebral ischemia and reperfusion+CoQ10 (IR+CoQ10). Group B,C,D,were feed with NS,Codonopsis pilosula,CoQ10 respectively .The common cervical arteries of the rats were transient blocked bilaterally, in association with bleeding from their tails and followed by reperfusion. The procedures were repeated once more again as above to establish a stable ischemic brain injury model. The levels of ATP, Na+, K +ATPase activity in brain tissue were determinated after 3,6,12h from the beginning of ischemia. Results The level of ATP and Na+,K +ATPase activity of Group B(IR+NS) were lower than those of Group A(SH)(P<0.05) and the level of ATP and Na+,K+ATPase activity of Group C(IR+Codo.) and Group D( IR+CoQ10)were both higher than those of GroupB(IR+NS)(P<0.05).There was no difference between the values of Group C and Group D.Conclusions Codonopsis pilosula could improve the energy metabolism of brain and had the protective effect on brain. It's effect is approach to that of CoQ10.