Abstract： Objective To study the spinal cord protection effect of cerebrospinal fluid drainage （CSFD）for patients undergoing thoracoabdominal aortic aneurysm surgery. Methods We randomly allocated 30 patients undergoing thoracoabdominal aortic aneurysm surgery in Beijing Anzhen Hospital from December 2008 to August 2009 into a CSFD group with 15 patients（12 males, 3 females; average age of 45.0 years） and a control group with 15 patients（11 males, 4 females; average age at 45.8 years）by computer. All the patients underwent replacement of ascending aorta and aortic arch, implantation of descending aorta stent, or thoracoabdominal aorta replacement. Some patients underwent Bentall operation or replacement of half aortic arch. Patients in the CSFD group also underwent CSFD. Serum S100B, glial fibrillary acidic protein and neuron-specific enolase were measured at set intraoperative and postoperative times. All the patients were scored preoperatively, 72 hours postoperatively, and before discharge according to the National Institutes of Health Stroke Scale and International Standards for Neurological Classification of Spinal Cord Injury. Results Central nervous system injury occurred in four patients in the control group： one died of both brain damage and spinal cord damage; one patient had spinal cord injury and became better after treatment by early CSFD; two patients had brain damage（one patient died, another patient had concomitant acute renal failure and acute respiratory failure, recovered and was discharged after treatment）. In the CSFD group, only one patient died of acute respiratory failure and subsequent multiple organ system failure, and all other patients recovered very well. There was no late death during three months follow-up in both groups. The average serum S100B, glial fibrillary acidic protein，and neuron-specific enolase concentrations of the CSFD group patients were significantly lower than those of the control group （F=7.153，P=0.012；F=3.263，P=0.082；F=4.927，P=0.035）. Conclusion Selected CSFD is a safe, effective and feasible procedure to protect the spinal cord from ischemic damage during the perioperative period of thoracoabdominal aortic aneurysm surgery.