Objective To investigate the causes and prevention strategies of postoperative spinal cord injury after anterior approach surgery for cervical spondylotic myelopathy. Methods The clinical data of 749 patients with cervical spondylotic myelopathy treated with anterior approach surgery from 2001 to 2009 were retrospectively studied.There were five patients with spinal cord dysfunction instantly or early after operation,including three males and two females at average age of 52 years (range,48-62 years).Two patients were combined with ossification of the posterior longitudinal ligament.The Japanese Orthopaedic Association (JOA) score was average 12.4(9-16)preoperatively.The surgeries included anterior cervical diskectomy(or corpectomy)and interbody fusion(iliac bone graft or cage or titanium mesh)and locking plates fixation.The blood loss was 50-200 ml.The symptoms included instant spinal cord injury in two patients,loss of the motor and feeling of both legs at 6 h after surgery in one,paralysis of one side limbs at 24 h after surgery in one and numbness of limbs at 5 days after surgery in one.Four patients were treated by large dose of methylprednisolone.Five patients underwent anterior exploration surgery,of which one patient received posterior cervical one-door expansive laminoplasty. Results The patients were followed up for average 16 months(12-24 months).The JOA score of four patients was recovered at three months and WaS better than preoperation after surgery.The function of spinal cord of one patient showed no improvement at one year after surgery.The causes for spinal cord injury included inappropriate surgical manipulation in decompression and haemostasis in two patients,insufficient decompression in one,epidural hematoma in one and absorbable hemostatic gauze in one. Conclusions The major causes of postoperative spinal cord injury in anterior approach surgery for cervical spondylofic myelopathy are the delayed postoperative injury.The spinal cord can recover to normal and has satisfactory prognosis if discovered promptly.We must avoid the spinal cord injury by surgical Manipulation that may result in permanent neurological deficits.