Shear　tests　on　rectangular　plate　sandstone　containing　two　pre-existing　holes　were　performed　to　analyze　the　shear　mechanical　responses　and　cracking　evolution　mechanisms.　With　generation　of　the　penetrating　fracture　surfaces,　both　shear　stress　and　normal　displacement　show　a　dramatic　drop.　Then,　during　the　shear　slipping　process,　the　shear　stress　increases　once　again　due　to　wear　and　shear　off　of　the　surface　asperities,　and　three　different　variation　trends　of　the　normal　deformation　including　shear　dilation,　fluctuation,　and　shear　contraction　are　respectively　identified.　The　role　of　ligament　length　and　normal　stress　on　several　key　indices　such　as　peak　shear　stress,　peak　normal　displacement　and　residual　shear　stress　was　investigated.　Violent　AE　(acoustic　emission)　responses　occur　along　with　penetration　of　the　fracture　surfaces,　and　in　the　shear　slipping　process,　AE　events　continue　to　occur　due　to　wear　of　surface　asperities,　while　the　increase　rate　of　accumulative　AE　events　declines.　Cracks　coalesced　at　the　rock　bridge　and　running　through　the　rock　matrix　form　the　main　failure　planes　of　the　samples.　From　the　PFC2D　simulation　results,　the　crack　clusters　first　initiate　from　hole-walls　and　coalesce　at　the　rock　bridge　for　a　small　ligament　length,　while　first　produce　the　main　failure　planes　at　the　right/left　rock　matrix　for　a　large　ligament　length.　The　total　number　of　micro　cracks　shows　a　＂calm　→　rapid　increase　→　decreasing　growth　amplitude＂variation　during　shearing,　and　the　induced　cracks　become　more　concentrated　for　a　larger　normal　stress,　implying　a　cumulative　damage　of　the　failure　surfaces.　©　2022　The　Author(s).