Abstract: Objective This is a study on the level of molecular biology to clarify the change regulation of inflammatory reaction and to investigate the effect of cyclooxygenase -2 inhibitor Celecoxib on memory function and the expression of Caspase-3 protein after traumatic brain injury (TBI) .Methods The model of severe closed TBI was established according to the method created by Marmarou. Adult Wistar rats (n=48) were randomly divided into TBI group , Celecoxib treatment group , sham operation group, normal controls. All rats were killed at each time point ,for detective COX-2 and Caspase-3 protein expression with West-blot and immunohistochemistry. Another 24 rats were randomly divided into TBI group , Celecoxib treatment group , sham operation group , and normal group . The cognitive dysfunction was evaluated using the Morris water maze (MWM) . Results The increased expression of protein COX-2 and Caspase-3 in brain after TBI, Celecoxib can apparently decrease COX-2 and Caspase-3 protein expression in brain, Celecoxib treatment group is compare with TBI group in distinction bears significance in statistics（p＜0.05）, and it can obviously shorten the latency of Morris water maze tests in 9、10day,the distinction bears have a significance in statistics（p＜0.01）.Conclusion Celecoxib can apparently decrease the expression of COX-2 and caspase-3, and inhibition of inflammatory reaction and apoptosis ，obviously shorten the latency of Morris water maze tests.

Key words: traumatic brain injury, COX-2 , Caspase-3 , Celecoxib , Morris water Maze