ObjectiveTo summarize the research progress on spontaneous facet fusion (SFF) after lumbar spine surgery, and provide reference for further research on SFF. Methods The definition, development, clinical significance, and related influence factors of SFF were throughout reviewed by referring to relevant domestic and foreign literature in recent years. Results SFF is a phenomenon of joint space disappearance and fusion of upper and lower articular processes, which starts in a ring shape from the outermost edges to the central regions. Currently reported SFF occurred after posterior lumbar pedicle screw fixation. SFF may increase the stability of surgical segments and relieve clinical symptoms of patients. SFF is closely related to the method of lumbar internal fixation, facet osteoarthritis, interbody fusion, age, body mass index, type B fracture (according to AO classification), and the operative segment. Conclusion Most reported SFF occur after posterior lumbar pedicle screw fixation, which can increase lumbar stability, but the mechanism and influencing factors remain to be further clarified.