The　multilayer　biaxial　weft　knitted　(MBWK)　fabrics　and　their　composites　have　been　widely　applied　in　fields　of　complex　structural　products　due　to　their　flexible　curved　deformability.　The　existence　of　stitch　in　MBWK　complicates　the　deformation　behavior　under　the　in-plane　shear　loading.　However,　it　has　not　been　well　explored　and　understood.　In　this　study,　a　numerical　micro-scale　virtual　fiber　modeling　was　built　to　investigate　the　in-plane　shear　performance　of　MBWK　by　considering　the　micro　geometric　features　and　fiber　property　that　are　difficult　to　be　characterized　solely　by　experiment.　The　strain　conditions　of　the　stitch　that　determine　the　fabric　shear　behavior　are　discussed.　The　deformation　behavior　leads　to　local　deformation　and　morphological　locking　of　the　stitch.　In　the　early　stage　of　the　shearing,　the　deformability　of　stitch　provides　enough　space　to　accommodate　the　rearrangement　of　axial　yarns.　In　the　shear　locking　stage,　the　restriction　of　stitch　and　compression　within　axial　yarns　at　high　shear　angles　restricts　the　axial　yarns　from　movement　in　the　loading　direction.　When　the　theoretical　shear　angle　is　20　degrees,　the　shear　angle　located　in　different　shear　regions　varies.　The　maximum　shear　angle　near　the　loading　area　is　19.1　degrees,　while　the　minimum　shear　angle　near　the　fixed　area　is　approximately　17　degrees.　The　results　illustrate　the　deformation　mechanism　of　MBWK　under　in-plane　shearing　and　provide　an　excellent　guidance　for　the　design　of　large　deformation　fabrics,　especially　for　curved　surfaces,　thus　realize　the　effective　utilization　of　fabrics　in　engineering　applications.