[Objective] To evaluate biomechanical stability and security of upper cervical hook-plate fixation and pedicle screw fixation by finite element method. The stress distribution of these fixations were also investigated. [Methods] Finite element software was used to establish the axis defect model and then the hook-plate fixation and pedicle screw fixation were loaded on the deletion model for calculation and analysis to obtain the ROM of each model and the stress cloud of the internal fixation model. [Result] Compared with the normal model, the defect model was unstable only under the condition of flexion. The stability of the two internal fixation models was significantly stronger than that of the normal model and the defect model. The stability of hook-plate model was slightly stronger than that of pedicle screw model only under lateral buckling condition, while it was worse under other conditions. In terms of stress, the maximum stress of hook-plate fixation was slightly less than that of pedicle screw fixation under forward bending condition, but it was obviously greater under other conditions. The stress of hook-plate fixation mainly concentrated on the position of hook-plate connection, while the stress of pedicle screw fixation is relatively average and the maximum stress area was mainly located at the tail of C1 screw. [Conclusion] The hook-plate fixation is obviously more stable than normal upper cervical spine and axis defect spine, but slightly worse than pedicle screw fixation, which can meet the requirements of clinical stability. Local stress is high in the connecting part of hook-plate, which is prone to fracture.