Abstract: Objective To study the effect of edaravone on learning memory function and its potential protective mech anism after traumatic brain in jury(TBI).Methods Male Sprague Dawley rats were divided randomly into three groups: control,traumatic,and edaravone treamtent group.TBI rat model was established according to the description of Marma rou's diffused brain injury.Changes of neuron morphous were observed with electron micro scope.The ERK1/2 pho sphorylation expression was detected with Western Blot.The learning and memory function were detected with Morris water maze.Re sults Compared wih the control group,some neurons displayed severe histopathologic injury.The ERK1/2 pho sphorylation 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 expres sions 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 laten cyperiod shortened(70.6±8.7,P<0.05).Conclusion Edaravine can dramatically miprove learning and memory function after TBI.Edarav one may down regulate ERK 1/2 activation a fter TBI.