Abstract: Objective To analyze the biomechanical characteristics of three different internal fixation methods for lumbar fusion by three-dimensional finite element (FE) methods. Methods The FE fixation models of physiological L4/5, unfixed fusion L4/5, TLFS, TLFS+LPS, BPS with facet joint complete osteotomy or partial osteotomy were established, respectively. The biomechanical characteristics of L4 centrum and implants under six kinds of motion states (spinal flexion, extension, lateral?bending?and?axial?rotation) in L4/5 fusion model and three fixation models were compared by FE analysis.Results L4 centrum average maximal displacement in L4/5 unfixed fusion model, TLFS model, TLFS+LPS model, BPS model were 1.4108mm, 0.6298mm, 0.3369mm, 0.2528mm（ facet joint complete osteotomy）；1.2967mm, 0.8449mm, 0.3409mm, 0.2738mm（ facet joint partial osteotomy）; Cage average maximal displacement were 0.4799mm, 0.3195mm, 0.1676mm, 0.1264mm（facet joint complete osteotomy）；0.3787mm, 0.3484mm, 0.1835mm, 0.1372mm（facet joint partial osteotomy）；Average maximal stress of screws and rods in 6 motions of TLFS、TLFS+LPS、BPS models were 178.34MPa, 79.55MPa, 56.33MPa（facet joint complete osteotomy）；142.29MPa，103.02MPa，59.69MPa（facet joint partial osteotomy）.Conclusion In Percutaneous Transforaminal Lumbar Interbody Fusion, the fixation effect of BPS model is similar to that of LPS+TLFS model. BPS can achieve the best spinal stability, and LPS+TLFS model is also a good fixation method. The stability of TLFS model alone was relatively poor, but it was still better than that of cage bone graft without internal fixation. In the absence of internal fixation, the preservation of the articular process significantly increased the stability of the spine.