The　rock　bolt-grout　interface　(BGI)　represents　the　weakest　link　in　anchorage　systems.　Under　cyclic　loading,　continuous　slip　and　closure　at　the　interface　lead　to　degradation　of　its　load-bearing　capacity　and　fatigue　damage.　To　investigate　the　fatigue　shear　behavior　of　the　BGI,　laboratory　shear　tests　were　conducted　to　provide　a　basis　for　calibrating　the　mechanical　parameters　in　simulations.　Subsequently,　a　series　of　numerical　simulations　of　cyclic　shear　on　the　BGI　were　performed.　The　number　of　cracks　increased　in　a　stepwise　manner　over　time,　initially　concentrated　on　the　left　side　of　the　BGI　and　then　gradually　extending　to　the　right,　ultimately　resulting　in　through-cracks.　High　frequency,　high　amplitude,　and　high　stress　levels　accelerated　crack　extension,　weakening　the　bonding　strength　at　the　BGI.　The　introduction　of　irreversible　strain　for　a　quantitative　analysis　of　the　fatigue　process　revealed　that　increases　in　frequency,　amplitude,　and　maximum　shear　stress　levels　significantly　accelerated　damage　accumulation　and　shortened　fatigue　life.　Additionally,　the　direct　shear　test　with　an　amplitude　of　0　revealed　creep　characteristics,　with　initial　shear　displacement　increasing　steadily　before　accelerating　due　to　damage　accumulation.　Fitting　analysis　indicated　that　increases　in　frequency,　amplitude,　and　maximum　shear　stress　level　significantly　raised　the　initial　shear　displacement　and　accelerated　its　growth　rate.