Abstract:[Purpose] Analyze the biomechanical characteristics of the new lumbar spine internal fixation system by finite element method, and demonstrate the clinical value of the new lumbar spine internal fixation system in reducing the loosening rate of internal fixation. [Methods] Acquire CT scan data of 60-year-old volunteers with osteoporosis, use Mimics, UG, and Abaqus software to build L4-5 vertebral body models, and build a new lumbar internal fixation system model (group A) and traditional pedicle screws on this basis. Internal fixation system model (group B), traditional pedicle screw internal fixation system + transverse connection model (group C), traditional pedicle screw internal fixation system + bone cement model (group D), Load in six states: forward flexion, extension, left and right lateral flexion, and left and right rotation, Compare the difference of the intervertebral range of motion, the peak stress of the internal fixation system and the peak stress of the bone around the nail channel under different motion states of each group of models.[Results]①Among the four groups of models, the surgical model of group A has the smallest intervertebral mobility in each state of motion, and the mobility during rotational movement is significantly less than that of the three groups B, C, and D, and the maximum is 34.92% less than that of group B.②In the four groups of models, the stress distribution of the internal fixation system in group A is more uniform, and the stress peak of the internal fixation system in group A is the smallest in each movement state, and the stress peak is significantly reduced compared to the three groups B, C, and D during rotation, and the maximum is higher than that of B The group decreased by 36.44%.③Among the four groups of models, the peak stress of the bone around the nail channel in group A was the smallest in each movement state, and the peak stress during the rotation movement was significantly reduced compared with the three groups B, C, and D, and the maximum was reduced by 26.94% compared with the B group. [Conclusion] the new lumbar spine screw internal fixation system has better stability and can effectively reduce the loosening rate of lumbar spine internal fixation.