Objective To study the protective role of nerve growth factor (NGF) on cerebral ischemic reperfusion injury and its effect on Bax expression. Methods The models of focal cerebral ischemic reperfusion in rats were made by occlusion middle cerebral artery using an intraluminal filament method. NGF was given through vena caudalis. The expression of Bax was studied by immunohistochemistry method and the change of brain was observed using pathological method.Results Bax positive cells in the cortex and striatum areas in ischemia-reperfusion group (115.25?15.07) were more than those in NGF treatment group (70.00?12.77) ((P