The study of nervous somatomedin IB (NRG IB) on cerebral ischemia reperfusion neurobehavioral function, infarct volume, brain water content, neuronal apoptosis and aquaporin 4 (aquaPorin a 4 and AQP4) expression, and to explore the neural regulation of the protective mechanism on Cerebral Ischemia reperfusion Injury. Method of application of the suture method to establish the arterial occlusion and reperfusion (a reperfusion middlecerebralarteryoeelusion mouse brain MCAO melon) model, the intervention by the internal carotid artery injection of NRG-IB (as well stay kg) the Bederson method to evaluate the animal’s neurobehavioral function, chlorine of triphenyl tetrazolium wow (tetrazoliumehloride, TI’C) staining of the volume of cerebral infarction, the water content of wet and dry weight determination of brain tissue, immunofluorescence staining was used to detect neuronal apoptosis, immunohistochemical staining of nerve cells AQP 4 expression . Results after cerebral ischemia and reperfusion injury, the animals were shown to the neurobehavioral dysfunction, ischemic hemisphere cerebral infarction lesions, accompanied by increased water content in brain tissue, nerve cells AQP 4 enhanced expression and neuronal apoptosis. NRG an IB treatment after ischemia 24h animals neurobehavioral dysfunction is significantly lighter than the control group, the decrease in the number of apoptotic nerve cells, significantly reduced infarct volume, p <0.05; brain water content and AQP-4 expression and control was no significant difference (P> 0.05). Ischemia and reperfusion 22h, 46h and 70h group, the five indicators compared with the corresponding control groups were significant differences (p <0.05). Changes in brain water content and AQP-4 expression was positively correlated (p <0.05). Conclusion neuregulin may be by blocking ischemia-induced apoptosis gene activation pathway, down AQP-4 expression in order to reduce cerebral edema and reduce the infarct volume, thereby reducing the degree of cerebral ischemia and reperfusion injury and neurological deficit symptoms, protect brain tissue and their functions.