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Objective To study the biomechanical properties of lumbar vertebrae under the various situations of pedicle screw fixation, and to provide the basis of choosing pedicle screws to fix vertebral pedicle screws in lumbar operations. Methods Firstly, 15 samples of fresh porcine multi-segment vertebrae, which were separated from the muscles around the vertebral body and the soft tissue and were kept the integrality of disc, ligaments, small joints and vertebrae, were divided into three groups and tested: 5 samples were fixed strongly with universal screws (Group A) ; 5 samples were fixed with one-way screws and universal screws (Group B) ;5 samples were fixed with one-way screws in a slight movement (Group C) . Secondly, the moment of couple forces of 3 N · m、4 N · m、5 N · m and 6 N · m were applied to the three group samples by a universal test machine, and the range of motions (ROM) of every vertebral segments and the whole vertebrae were measured under flexion (FL) , posterior extension (EX) , left sidebend (LB) and right side bend (RB) . Results In aforementioned four experimental conditions, the results showed that the ROMs of group fixed only with universal screws were smallest; the ROMs of group fixed only with one-way screws were largest; the ROMs of Group C were 139%, 112%, 135. 4%, and 143. 3% of the counterpart of Group A under FL, EX, LB, and RB respectively; there were not significant errors in the bending property before and after the experiments among the all three groups. Conclusions The combination of pedicle screw fixation has a great effect on the stability and flexibility of vertebral activity. The universal screw fixation is more suitable for patients who need strong stability, and one-way screw fixation can improve the flexibility of left and right bending. This paper may provide a theoretical reference for clinical choice of reasonable surgical program.