To investigate whether protective effect of tacrolimus postconditioning on rats' spinal cord ischemia-reperfusion injury is mediated by up-regulation of activity of endogenous antioxidant enzymes and down-regulation of production of oxygen free radicals. Ninety male Sprague-Dawley rats were randomly divided into ischemia-reperfusion (IR) group, tacrolimus postconditioning (TP) group and sham operation (SO) group. The model of spinal cord ischemia was prepared by means of catheterization through femoral artery and balloon dilatation. IR group underwent reperfusion 20 min after spinal cord ischemia. TP group experienced a single injection of tacrolimus (0.5 mg/kg) through the left common carotid artery at the onset of reperfusion. SO group received femoral artery catheterization only. Fluoro spectro photometry was employed to detect the level of reactive oxygen species (ROS) in injured spinal cord segment at 15 minutes after reperfusion. The content of malondialdehyde (MDA) and activity of antioxidant enzymes including superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GSH-PX) were determined at 15 minutes, 1, 6, and 24 hours after reperfusion respectively. BBB scale was conducted to evaluate hindlimb motor function at 14 days after reperfusion. The level of ROS in TP group was significantly lower than that in IR group at 15 minutes after reperfusion. The activity of SOD was significantly higher in TP group than in IR group at all observational time points, while the activities of CAT and GSH-PX were significantly higher in TP group than in IR group at 1 and 6 hours after reperfusion. The content of MDA in TP group was significantly less than that in IR group at all observational time points. The motor function score of TP group was significantly superior to that of IR group at 14 days after reperfusion. Tacrolimus post conditioning can improve activity of endogenous antioxidant enzymes, decrease production of oxygen free radicals, suppress lipid peroxidation, and thereby promote functional recovery after spinal cord ischemia-reperfusion injury in rats.