To perform bioinformatics analysis on spasticity-related genes after spinal cord injury (SCI) in rats, and explore the molecular mechanisms underlying spasticity after SCI. Methods: GSE16710, the gene expression profile chip data related to spasticity after SCI, were downloaded from the GEO database. Differentially expressed genes (DEGs) were identified using the online tool GEO 2R based on the screening criteria of P<0.05 and |log2FC|≥1, and visualized using volcano maps. The identified DEGs were subjected to GO functional enrichment and KEGG pathway analyses using the DAVID database, and the results were visualized using ImageGP. Protein-protein interaction (PPI) network analysis of DEGs was constructed using the STRING database and visualized using Cytoscape software; the top 10 key genes in the PPI networks were selected using the CytoHubba plugin and the degree values of differentially expressed proteins (DEPs). Results: A total of 313 DEGs were identified, of which 92 were upregulated genes and 221 were downregulated genes. GO enrichment analysis showed that the DEGs were mainly involved in biological processes such as the regulation of glutamatergic synaptic transmission, positive regulation of synaptic transmission, regulation of neuronal projection development, and regulation of phosphatidylinositol 3-kinase signaling. KEGG pathway analysis revealed that the DEGs were mainly enriched in long-term potentiation, glutamatergic synapse, MAPK signaling pathway, and cAMP signaling pathway. PPI analysis identified the top 10 key genes, including Mapt, Gad1, Gria2, Fmr1, Reln, Mbp, and Cav1. Conclusion: Through bioinformatics analysis of key DEGs and pathways involved in spasticity after SCI, this study provides insights into the underlying molecular mechanisms and their roles in the occurrence and development of spasticity, thus providing a theoretical basis for the treatment of this disease.