This　study　investigates　the　fracture　behaviors　and　crack　propagation　characteristics　of　granite　under　cyclic　loading　and　unloading.　Semi-circular　bending　(SCB) specimens　were　subjected　to　three-point　bending　tests　integrated　with　acoustic　emission　(AE)　monitoring,　3D　scanning,　and　digital　image　correlation　(DIC)　technologies.　The　experimental　protocols　included　static　loading,　tiered　constant　amplitude　(TCA) cyclic　loading,　and　variable　amplitude　(VA)　cyclic　loading.　The　results　show　that　cyclic　loading　significantly　influences　fracture　toughness　by　modifying　the　internal　microstructure　of　granite.　During　cyclic　loading　and　unloading,　microcracks　repeatedly　open　and　close,　leading　to　a　denser　microstructure　and　increased　stiffness.　3D　scanning　analysis　revealed　that　cyclic　loading　produces　rougher　and　more　tortuous　fracture　surfaces　and　trajectories　as　compared　to　static　loading.　AE　activity　under　VA　cyclic　loading　indicated　the　generation　of　numerous　microcracks　and　the　formation　of　a　larger　microcrack　zone　with　lower　energy　release,　whereas　TCA　cyclic　loading　was　characterized　by　lower-frequency　AE　signals.　This　suggests　that　incomplete　unloading　and　shorter　loading　durations　in　TCA　conditions　deteriorate　the　intergranular　interlocking　capacity　of　mineral　grains,　promoting　intergranular　crack　formation.　DIC　analysis　demonstrated　that　VA　cyclic　loading　facilitates　microcrack　development,　resulting　in　increased　microcrack　extension　lengths　and　a　larger　fracture　process　zone (FPZ)　at　peak　load.　Furthermore,　the　higher　ratio　of　normalized　crack　mouth　opening　displacement (CMOD),　normalized　crack　tip　opening　displacement (CTOD),　and　displacement　jumps　during　the　cyclic　loading　and　unloading　process　of　TCA　conditions　indicate　greater　plastic　deformation　and　cumulative　damage.　This　work　enhances　the　understanding　of　how　cyclic　load　affects　rock　fracture　characteristics　and　elucidates　the　mechanisms　underlying　fatigue　failure　in　granite,　providing　valuable　insights　for　the　design　and　assessment　of　rock　engineering　structures　subjected　to　cyclic　stresses.　©　The　Author(s),　under　exclusive　licence　to　Springer-Verlag　GmbH　Austria,　part　of　Springer　Nature　2025.