This　study　investigated　the　thermal　cycling　effects　on　the　dynamic　behavior　of　granite　and　described　its　microstructure.　The　specimens　were　subjected　to　various　numbers　of　thermal　cycles　(0,　1,　3,　5,　and　7　cycles)　at　temperatures　ranging　from　25　to　500　degrees　C.　Then,　ultrasonic　wave　tests　and　split　Hopkinson　pressure　bar　(SHPB)　tests　(with　different　impact　gas　pressures　of　0.25,　0.28,　and　0.31　MPa)　were　performed　to　study　the　thermal　cycling　effects　on　the　P-wave　velocity,　P-wave　modulus,　dynamic　compressive　strength,　and　impact　failure　pattern　of　the　granite　specimens.　Finally,　scanning　electron　microscopy　(SEM)　was　performed　to　analyze　the　micromechanism　of　the　dynamic　property　degeneration　of　the　granite　specimens.　The　results　show　that　the　dynamic　properties　of　the　P-wave　velocity,　P-wave　modulus,　and　dynamic　compressive　strength　exponentially　decrease　as　the　number　of　thermal　cycles　increases.　The　decreases　in　the　dynamic　properties　mainly　occur　during　the　first　thermal　cycle,　and　the　P-wave　modulus　and　dynamic　strength　decrease　by　67.5%　and　8.4-16.3%,　respectively.　Moreover,　a　higher　dynamic　compressive　strength,　smaller　fragments,　and　more　fine　powder　are　generated　by　impact　failure　with　a　larger　strain　rate.　Smaller　fragments　and　more　fine　powder　are　observed　after　impact　failure　as　the　number　of　thermal　cycles　increases.　The　tests　further　reveal　that　the　dynamic　properties　of　thermally　damaged　granite　are　closely　related　to　the　microcracks　induced　by　thermal　cycling.