To observe the possible mechanisms of the extraction of Naotai Fomula (NTF) on the regional cerebral ischemia so as to provide treatment to the more and more common disease-cerebral arterial thrombosis.Methods:Self-made Naotai Fomula were given to SD rats by gavage administration for 7 days before the occlusion of the middle cerebral artery(MCAO)operation. After the operation, the TTC staining was used to show the apoptosis of the hippocampal neurons and RT-PCR was used to show gene expression of GRP78 and CHOP of the ischemia cerebrum of rats.Results:Firstly, the extraction of NTF could improve the neuro behavior score and at the same time decrease the death rate of the hippocampal neuron after MCAO operation. Secondly, the extraction of NTF elevated the expression of GRP78 and decreased the expression of CHOP.Conclusion:Firstly, ER Stress is involved in the hippocampal neuronal injury caused by the ischemia in the rats. Secondly, the extraction of NTF can regulate ERS especially in the early stage after acute ischemia of the brain in rats.