Abstract： Objective To determine whether the X-irradiation of the contusion site can improve the recovery of locomotor function following spinal cord injury in rats. Methods The spinal cords of 70 male Wistar rats at the level of T10 were contused with a weight-drop apparatus similar to the NYU impactor. Ten rats were chosen as control group. The other 60 rats were equally randomized into 6 groups and localized X-irradiation (20 Gy) of the contusion site was performed on rats in these 6 group 20 min, 1,2,4, 7 and 17 d after the injury, respectively. Locomotor function was determined by the Basso, Beattie and Bresnahan Locomotor Rating Scale (BBB). Following 6 w of behavioral evaluation, the spinal cords were received histological examination. Results X-irradiation of the contusion site 20 min, 1 and 2 d after the injury significantly improved the recovery of locomotor function as compared with no X-irradiation (control group, P<0.05); and the improvement in the 2nd and 3rd w were the quickest among all the time points. Increased amount of spared spinal cord tissue in the X-irradiation groups was found as compared with that in the control group. Conclusion X-irradiation of the contusion site following contusion at an early stage can protect the spared spinal cord tissue and help the recovery of locomotor function.