Objective: To analysis the safety accuracy and effectiveness of simultaneous monitoring of somatosensory evoked potential(SEP) and motor evoked potential (MEP) in severe scoliosis surgery．Methods: A retrospective study was performed in 65 severe scoliosis patients who underwent spinal orthopedic surgery from June 2017 to May 2019．All patients were operated under general anesthesia. Simultaneous monitoring of SEP and MEP was performed． Results: There were 19 of 65 cases appeared positive for evoked potentials during the combined monitoring, 10 of which were both positive, intra-operative wake-up tests were positive, after the corresponding treatment, all the surgerys successfully completed. And 6 cases had no obvious neurological dysfunction after the surgery, 3 cases had transient decline in muscle strength of quadriceps femoris and iliopsoas, intraoperative methylprednisolone shock treatment was performed in one case, and postoperative intravenous dexamethasone dose was 10mg/d, after those treatment, the muscle strength gradually returned to normal after one week, and the function was good after 1-year follow-up. SEP alerted alone in 7 cases, which were judged to be false positive after strict examination and wake-up tests were not conducted, and the surgerys were not interrupted with good postoperative function. MEP alerted alone in 2 cases, and MEP did not return to normal after excluding other factors, therefore the intra-operative wake-up tests were negative, and the surgerys were successfully finished with good postoperative function. Conclusions: Combined monitoring intra-operative SEP and MEP could reduce false positive rate compared with single monitoring, increase the surgery safety, reduce the interference with the surgery process, and shorten the surgery time, reduce bleeding and postoperative recovery is better, demonstrated good sensitivity and accuracy. Both evoked potentials positive indicated the spinal cord injury.