Objective: To investigate the protective effect and the mechanism of ginkgolide N (GN) model of focal cerebral ischemia reperfusion injury in rat. Method: The model of ischemia (2 hours) and reperfusion (22 hours) induced by thread approach was reproduced for evaluating the effect of GN on the neurological symptoms, infarction area percentage, rate of brain water, content of malondialdehyde (MDA), activitiy of SOD in the brain tissues and the intracellular _i in the cerebral cortex. Result: Compared with I/R group, GN high dosage group, middle dosage group and nimodipine group relieved signfecantly the neurological symptoms and reduced the cerebral infarction area percentage and content of brain water in rats, meanwhile all GN and nimodiping groups ameliorated the activity of SOD and decreased MDA content and[Ca²⁺]_i level after ischemia and reperfusion injury. Conclusion: GN has the protective effect on rats with cerebral focal ischemia and reperfusion injury, which may be related to that GN can reduce the content of brain water, infarction area percentage, content of MDA and[Ca²⁺]_i level and increase the activity of SOD.