Objectives To evaluate the biomechanical stability of an new semirigid pedicle screw fixation device. Methods A model of destabilized spine was produced on six specimens of fresh calf cadaver spine from T11 to L1. Three fixation devices, (NRD、NSRD and RD) were ordinal applied in the specimens to strengthen the destabilized level. Ranges of three dimensional movements were measured in intact, destabilized and stabilized specimens, respectively. Results Three fixation devices all could provide significant stability for destabilized segment in flexion-extension, lateral bending and axial rotation. The range of motion (ROM) of the spine fixed with RD at T11-T12 was also significantly increased in comparison with the intact spine under flexion, extension and right axial rotation P(<0.05). The ROM of the stabilized spine with NSRD or NRD approximated the ROM of the intact spine at each motion of T11-T12 level.C onclusion The semirigid device could make the offer to a design that may not affect the ROM of adjacent segments while maintaining stability similar to that of rigid systems.