Objective To compare the gene expression changes in astrocytes before and after injury. Methods The total RNA from the scratched spinal cord astrocytes two days after injury (injury group) and from the unscratched astrocytes (control group) were extracted for construction of cDNA difference library by means of Switching Mechanism At 5’ end of the RNA Transcript (SMART) and suppression subtractive hybridization (SSH) techniques. The change of the gene expression was identified in astrocytes two days after trauma and the sequences of different expressed segments were analyzed for searching their homology in NCBI BLAST database so as to know the whole change trend of the genes two days after scratch injury of rat spinal cord astrocytes. Results At day 2 after scratch injury of spinal cord astrocytes in newborn rats, expressions of 17 genes including heat shock protein 70, acidic fibroblast growth factor and calmodulin II were up-regulated but those of genes such as ?-actin down-regulated. Conclusion The gene expression is either up-regulated in proteins like heat shock protein 70 or down-regulated in proteins like ?-actin in the reactive astrocytosis after scratch injury of spinal cord astrocytes in rats.