Severe cervical degenerative disease was usually difficult in decision making which complicated with multi-segment degeneration. It associated with severe spinal cord compression, ligament ossification, or cervical deformity. Anterior cervical decompression and fusion ( ACDF ) in treating severe cervical degeneration is still controversial, including interbody fusion system with Zero-profile cage for cervical curvature, correlation between cervical sagittal alignment and the health-related quality of life, C5 nerve root palsy postoperatively, application of microscopic assistant surgery and IONM in the cervical spine surgery, the relationship between kinematic parameters ICR and cervical degeneration.