Abstract: Objective To study the effect of methylprednisolone on regional spinal cord blood flow,electrophysiological function,histopathological changes and motor functional recovery. Methods Thirty-six canines were randomly divided into experimental group（n=18） and control group（n=18）.Canines in experimental group received intravenous injection with methylprednisolone（30mg/kg）,5.4mg/kg each hour,while those in control group received intravenous injection with 0.9% sodium chloride 5min after SEP was disappeared.SEP and blood flow in spinal cord were measured during the 90min sustained compression,which was repeated 3h after decompression and scored.Lesion size was measured by histological analysis 28 days after decompression. Results SEP occurred in 7 canines of experimental group during decompression.However,no SEP was found in control group.SEP occurred in 3 canines of both groups after decompression.The blood flow volume in spinal cord was greater in canines with SEP than in those without SEP（P＜0.05）,returned to its basal level in experimental group 5min after decompression,and was significantly greater than that in control group（P＜0.05）.The motor function of hind limbs was rather rapidly recovered in experimental group but not in control group.The lesion size of spinal cord was significantly different between the two groups.The pathological change was correlated with SEP,blood flow in spinal cord,and recovery of motor function. Conclusion Methylprednisolone can significantly protect and restore the function of nerves and increase the regional blood flow in spinal cord.