Background　Little　is　known　about　the　biomechanical　performance　of　different　internal　fixations　in　oblique　lumbar　interbody　fusion　(OLIF).　Here,　finite　element　(FE)　analysis　was　used　to　describe　the　biomechanics　of　various　internal　fixations　and　compare　and　explore　the　stability　of　each　fixation.　Methods　CT　scans　of　a　patient　with　lumbar　degenerative　disease　were　performed,　and　the　l3-S1　model　was　constructed　using　relevant　software.　The　other　five　FE　models　were　constructed　by　simulating　the　model　operation　and　adding　different　related　implants,　including　(1)　an　intact　model,　(2)　a　stand-alone　(SA)　model　with　no　instrument,　(3)　a　unilateral　pedicle　screw　model　(UPS),　(4)　a　unilateral　pedicle　screw　contralateral　translaminar　facet　screw　model　(UPS-CTFS),　(5)　a　bilateral　pedicle　screw　(BPS)　model,　and　(6)　a　cortical　bone　trajectory　screw　model　(CBT).　Various　motion　loads　were　set　by　FE　software　to　simulate　lumbar　vertebral　activity.　The　software　was　also　used　to　extract　the　range　of　motion　(ROM)　of　the　surgical　segment,　CAGE　and　fixation　stress　in　the　different　models.　Results　The　SA　group　had　the　greatest　ROM　and　CAGE　stress.　The　ROM　of　the　BPS　and　UPS-CTFS　was　not　significantly　different　among　motion　loadings.　Compared　with　the　other　three　models,　the　BPS　model　had　lower　internal　fixation　stress　among　loading　conditions,　and　the　CBT　screw　internal　fixation　had　the　highest　stress　among　loads.　Conclusions　The　BPS　model　provided　the　best　biomechanical　stability　for　OLIF.　The　SA　model　was　relatively　less　stable.　The　UPS-CTFS　group　had　reduced　ROM　in　the　fusion　segments,　but　the　stresses　on　the　internal　fixation　and　CAGE　were　relatively　higher　in　the　than　in　the　BPS　group;　the　CBT　group　had　a　lower　flexion　and　extension　ROM　and　higher　rotation　and　lateral　flexion　ROM　than　the　BPS　group.　The　stability　of　the　CBT　group　was　poorer　than　that　of　the　BPS　and　LPS-CTFS　groups.　The　CAGE　and　internal　fixation　stress　was　greater　in　the　CBT　group.