Yuan xx ,female ,49 years old ,L5 spondylolisthsis with uncomplete paraplegia.This patient had two operations in other two hospital for L5 spondylolisthesis ,when sdmicted he had a serve lumbago and his low extremities were uncomplete paraplegic .On April 11st 2005,under general anesthesia ,the patient had the operation of L5 spondylollisthesis posterior open reduction ,spinal cord decompression L4/5 interveterbral eage bone grafting ,external ,fixation with Moss-Miamisystem,After operation ,L5 received anatomic reduction MRI showed complete decompression of spinal cord ,the lumbago remitted after operation ,paraplegia of the low extremities mmbegan to recover.