Objective： To study the nerve degeneration of lower extremity after paraplegia. Methods: (1) The spine cord of experimental dogs were severed between T11-12. The section of main nerve trunks of lower extremities were studied under microscope after 3-6 weeks; (2) the sural nerve of later paraplegic patients were analyzed. Results: No obvious degeneration was found in the nerve of lower extremities of experimental dogs and later paraplegic patients. Conclusion: No obvious degeneration is found in lower extremity nerve if the injury plane is higher than T11.