While　drilling　deep　or　ultra-deep　wells　in　hard　rock　formations,　there　are　significant　problems　such　as　easy　wear　of　drilling　cutters　and　a　low　rate　of　penetration　(ROP),　and　rotary　percussion　drilling　technology　is　one　of　the　essential　techniques　for　improving　drilling　efficiency.　However,　there　is　currently　limited　research　on　the　compatibility　of　rotary　percussion　drilling　tools,　polycrystalline　diamond　compact　(PDC)　cutters,　and　hard　rock　formations.　Considering　the　motion　mechanism　of　rotary　percussion　drilling　tools,　a　three-dimensional　rock-breaking　numerical　model　was　established　for　different　cutters　(planar,　axe-shaped,　and　triple-ridged)　under　impact　loads.　Penetration　depths,　cutting　widths,　and　rock-breaking　volumes　of　different　cutters　under　static　and　dynamic　load　coupling　were　analyzed.　Changes　in　tensile,　compressive,　and　shear　stresses　during　the　cutter　rock-breaking　process　were　compared,　revealing　the　different　cutter　rock-breaking　mechanisms　under　impact　loads.　The　cutter　rock-breaking　laws　under　different　impact　amplitudes　and　frequencies　were　analyzed　quantitatively,　and　the　differences　in　rock-breaking　effects　of　different　cutters　under　various　geological　conditions　were　assessed.　The　results　indicated　that　cutter　penetration　depth　during　rotary　percussion　drilling　could　be　increased　by　16.04%　compared　to　that　during　conventional　drilling.　Under　the　same　impact　load,　the　rock-breaking　effects　of　different　cutters　on　hard　and　soft　rocks　exhibited　similar　variation　patterns.　The　penetration　depth　followed　the　order　axe-shaped　＞　triple-ridged　＞　planar　cutters,　with　an　average　tangential　order　of　triple-ridged　＜　axe-shaped　＜　planar　cutters.　When　drilling　through　hard　rock,　the　average　penetration　depths　of　planar,　axe-shaped,　and　triple-ridged　cutters　were　5.57,　6.06,　and　3.91　mm,　respectively.　The　average　tangential　forces　were　670.57,　541.76,　and　347.89　N,　respectively.　During　the　transition　from　soft　to　hard　rock　during　drilling,　the　tangential　forces　of　the　planar,　axe-shaped,　and　triple-ridged　cutters　increased　by　8.41%,　3.21%,　and　2.64%,　respectively.　The　planar　cutter　experienced　the　most　significant　instantaneous　tangential-force　change　and　was　more　prone　to　impact　damage.　Increasing　the　amplitude　of　the　axial　stress　waves　helps　enhance　the　penetration　depth　of　the　drill　bit,　whereas　increasing　the　frequency　of　the　stress　waves　can　reduce　the　intensity　of　fluctuations　during　drill-bit　penetration　and　increase　drill-bit　stability.　The　research　results　provide　insights　into　optimizing　drilling　cutters　and　engineering　parameters　during　rotary　percussion　drilling.