Researchers conducted a retrospective study. The study aimed to determine the auxiliary relevance of descending neurogenic–evoked potential (DNEP) for motor-evoked potential (MEP) during severe spinal deformity surgery when MEP-positive events occur. A total of 205 instances of severe spinal deformity repair were investigated retrospectively. In total, 74 MEP-positive cases were divided into 2 subgroups: DNEP (+) and DNEP (−). The neurological functions were assessed using the MEP recovery, wake-up test, and Frankle grade. The long-term and perioperative neurological outcomes were evaluated. The DNEP (−) and DNEP (+) groups had significant differences in preoperative scoliosis and kyphosis angles. Patients in the DNEP (−) group improved their MEP more (81.5%) than those in the DNEP (+) group (53.2%). In the Wake-up test, the DNEP (−) group had 59.3% motor function deficiency instances, compared to 87.2% in the DNEP (+) group. Immediately after the surgery and during follow-up, more patients in the DNEP (−) group had normal nerve function (Frankel level E) than those in the DNEP (+) group. After severe spinal deformity surgery, MEP-positive subjects with intraoperative DNEP (−) had a better prognosis. Intraoperative DNEP might be viewed as a valuable quantitative tool to help MEP in monitoring neurological injury, and it could also be used as a stand-in monitoring technique if MEP was unavailable.