Objective To investigate the protective effect of ischemic pre-conditioning(IPC) on the spinal cord injury associated with abdominal aortic cross-clamping. Methods Forty-eight New Zealand white rabbits were randomly divided into IPC group and ischemic group. The concentrations of endothelin-1(ET-1), prostacyclin(PGI_2) and thromboxane A_2(TXA_2) in spinal cord were measured at six different time intervals, before ischemic, 40 minutes after ischemic, 2 hours,8 hours,24 hours and 72 hours after reperfusion. Neurologic function and pathological changes were documented. Results In IPC group, ET-1 level, TXB_2 level and TXB_2/6-keto-PGF_ 1? ratio were significantly reduced, while 6-keto-PGF1? level was significantly increased compared with that of ischemic group (P