Objective: To evaluate clinical results and changes in cervic sagittal parameters after anterior cervical discectomy and fusion (ACDF) and to analyze the difference on clinical prognoses among treatment of different surgical segments. Methods: A retrospective study was performed in 52 cases of cervical disc herniation from February 2013 to January 2016 in the First Affiliated Hospital of Nanjing Medical University, who were undertaken by ACDF. Before and after the operations, cervical sagittal parameters were measured in MRI, including C0C2 angle, C2C7 angle, T1 slope, neck tilting and thoracic inlet angle. Therapeutic effects were evaluated by pain visual analogue scale (VAS) and Japanese Orthopaedic Association Scores (JOA). Results: The C2C7 angle and T1 slope were increased with the decreased neck tilting postoperatively. Also,the scores of VAS and JOA were improved after ACDF with a significant difference (P<0.05). Compared preoperative and postoperative results among single-level segment, double-levels segments and multiple-levels segments treatment, there were significant differences in the duration of operation and the amount of bleeding (P value =0.001). However, no statistical difference was found in cervical sagittal parameters changes and clinical improvement rate. Conclusion: Anterior cervical discectomy and fusion for cervical spondylosis comes out with a good therapeutic effect, which could improve the cervical curvature and increase the T1 slope to restore cervical sagittal balance. No significant difference was found in the changes of cervical sagittal parameters for different segements as well as clinical prognoses postoperatively in the treatment of cervical disc herniation.