OBJECTIVE: To design a new type of atlas vertebral lamina hook, construct a vertebral lamina screw combined with a new iliac vertebral lamina hook internal fixation system, and use a cadaver specimen for biomechanical testing to evaluate the internal fixation system at the atlantoaxial asymmetry. Biomechanical stability in internal fixation. METHODS: Six fresh cervical cadaver specimens (C0-C3) were selected and placed under a load of 1.5 Nm. The three-dimensional motion measurement system of the spine was used to measure the flexion and extension of the C1-2 segment, the left and right lateral curvature, and the axial rotation. Range of motion (ROM) and compare it in pairs. The experiment was performed according to the complete specimen model (complete group), atlantoaxial instability specimen model (stability group), bilateral atlantoaxial joint screw and Gallie fixed bone graft model (bilateral TAS+G group), bilateral sputum Axial transarticular screw combined with new atlas vertebral plate fixation model (bilateral TAS+H group), one side atlantoaxial transarticular screw and contralateral vertebral lamina screw combined with new axillary vertebral plate hook asymmetry The order of the fixed bone graft model (asymmetric group) was performed, and then the range of motion of the anterior-posterior flexion and extension, left and right lateral curvature, and axial rotation obtained by biomechanical measurement was statistically analyzed. RESULTS: Three fixations significantly improved atlantoaxial stability relative to the intact and unstable group models. The ROM of the three internal fixation group models was significantly reduced compared with the intact group and the instability group model, and the difference was statistically significant (P<0.05). Among the three internal fixation groups: the bilateral TAS+G fixation group has the smallest ROM in the direction of flexion and extension and the left and right lateral curvature, and the bilateral TAS+H internal fixation group has the smallest ROM in the direction of axial rotation. The asymmetric internal fixation group ROM was larger than the other two groups in the flexion and extension, the left and right lateral curvature, and the axial rotation direction, but the difference was not statistically significant (P>0.05). Conclusion: The atlantoaxial articular screw and the contralateral vertebral lamina screw combined with the new axillary vertebral plate hook asymmetric fixation bone graft can provide good biomechanical stability and have certain clinical guiding significance.