Objective To explore the expression and distribution of cyclin dependent kinase 11 (CDK11) after transected spinal cord injury (tSCI). Methods tSCI was performed at T9 in adult SpragueDawley (SD) rats. The rats were sacrificed 1day, 3days, 5days, 7days, 14days after operation respectively. Western blotting was used to detect the changes of CDK11 protein expression after tSCI,and the distribution and localization of CDK11 in spinal cord were investigated by immunohistochemical staining and immunofluorescence double staining. Results Western blotting analysis showed the expressions of CDK11SUP>p58/SUP> and CDK11SUP>p110/SUP>, which were the two major isoforms of CDK11, increased at first and then had a decrease tendency in both broken ends of the transected spinal cord. CDK11SUP>p58/SUP> was enhanced on the 3rd day and remained high level until the 7th day; while CDK11SUP>p110/SUP> was also increased, on the 3rd day but went down rapidly after the 5th day. Immunohistochemistry staining was indicated that CDK11 was distributed evenly in the normal spinal cord. On the 3rd day, the staining was elevated obviously in both white and grey matter. Immunofluorescence double staining suggested that CDK11 was colocalized with neuronal neclei (NeuN), cyclic nucleotide 3′phosphohydrolase （CNPase） and glial fibrillary acidic protein (GFAP).Conclusion The expression of CDK11 undergoes spatiotemporal changes after tSCI. These alterations may be