ObjectiveTo review the research on the reasons of unplanned reoperation (URP) for degenerative lumbar spine diseases, and to provide new ideas for improving the quality of surgery for degenerative lumbar spine diseases. Methods The literature about the URP of degenerative lumbar spine diseases at home and abroad in recent years was reviewed and analyzed. Results At present, the reasons for URP include surgical site infection (SSI), hematoma formation, cerebrospinal fluid leakage (CSFL), poor results of surgery, and implant complications. SSI and hematoma formation are the most common causes of URP, which happen in a short time after surgery; CSFL also occurs shortly after surgery but is relatively rare. Poor surgical results and implant complications occurred for a long time after surgery. Factors such as primary disease and surgical procedures have an important impact on the incidence of URP. ConclusionThe main reasons for URP are different in various periods after lumbar spine surgery. Interventions should be given to patients with high-risk URP, which thus can reduce the incidence of URP and improve the surgery quality and patients’ satisfaction.