[Objective] To explore the clinical outcomes of single open-door laminoplasty for ossification of the posterior longitudinal ligament (OPLL) in cervical and upper-thoracic spine. [Methods] From May 2017 to February 2019, a total of 21 patients underwent single open- door laminoplasty for continuous OPLL in cervical and upper- thoracic spine. [Results] All the patients had operation completed smoothly without serious complications, such as cerebrospinal fluid leakage and epidural hematoma. As time went during the follow-up last- ed for 9~24 months, the pyramidal tract sign, JOA, VAS and NDI scores significantly improved (P＜0.05) . One patient developed severe C5 nerve palsy, which was relieved after symptomatic treatment. In terms of imaging, the cervical lordosis angle decreased at 6 months after op- eration and at the latest follow-up compared with that preoperatively, but the difference was not statistically significant (P＞0.05) , while the sagittal diameter of the spinal canal increased significantly (P＜0.05) . During the follow-up period, no reclosing and the shaft fracture were noted in anyone of them. [Conclusion] Single posterior open-door extended laminoplasty does achieve sufficient spinal cord decompression, satisfactory neurological function improvement with low complications and satisfactory clinical efficacy for continuous OPLL in cervical and upper-thoracic spine.