Abstract: Objective To study the effect of edaravone on learning-memory function and its potential protective mechanism after traumatic brain injury(TBI).Methods Male Sprague-Dawley rats were divided randomly into three groups:control,traumatic,and edaravone treatment group.TBI rat model was established according to the description of Marmarou's diffused brain injury.Changes of neuron morphous were observed with electron microscope.The ERK1/2 phosphorylation expression was detected with Western Blot.The learning and memory function were detected with Morris water maze.Results Compared wih the control group,some neurons displayed severe histopathologic injury.The ERK1/2 phosphorylation expressions were significantly enhanced at 1hr(3.79±0.79),6hr(6.60±1.19),24hr(9.68±1.79),and 48hr(3.34±0.82).The mean of latency period in traumatic group(230.9±20.9s) was longer than that of in the control group(50.7±4.9s).Compared to traumatic group,the neuronal histopathologic injury decreased,and the ERK1/2 phodphorylation expressions were decreased at 6hr(3.48±1.49),24hr(5.39±2.03),48hr(1.90±0.72),(P<0.05 for all).The mean of latency period shortened(70.6±8.7,P<0.05).Conclusion Edaravine can dramatically improve learning and memory function after TBI.Edaravone may down-regulate ERK1/2 activation after TBI.