Torsional　percussive　drilling　tool　was　designed　to　reduce　the　risk　of　stick-slip　and　improve　drilling　efficiency,　but　there　are　few　studies　on　the　influence　of　torsional　impact　parameters,　including　amplitude,　frequency,　waveform,　on　the　rate　of　penetration　(ROP)　while　drilling　the　hard　rock.　The　design　of　the　torsional　percussive　drilling　tool　was　proposed,　and　the　mathematical　model　of　torsion　hammer　movement　was　developed,　the　Riedel-HiermaierThoma　(RHT)　rock　dynamic　material　model　was　applied　to　analyze　the　rock-breaking　process　of　the　tool.　A　numerical　model　of　hard　rock　cutting　with　a　single　polycrystalline　diamond　composite　(PDC)　bit　cutter　was　established,　the　influences　of　amplitude,　frequency,　time　parameters,　and　waveforms　on　the　penetration　depth　of　the　PDC　bit　cutter　were　analyzed　in　the　process　of　torsional　percussive　drilling.　The　results　showed　that　the　numerical　simulation　results　were　in　good　agreement　with　the　indoor　test　results,　which　verified　the　correctness　of　the　numerical　simulation.　Compared　with　conventional　drilling,　the　penetration　depth　of　torsional　percussive　drilling　was　increased　by　20.0%,　and　the　cutting　debris　particles　were　smaller,　which　was　conducive　to　improving　ROP　and　reducing　stick-slip　vibration　of　the　bit.　With　the　increase　of　the　peak　value　of　torsional　percussive　amplitude,　the　penetration　depth　of　the　cutter　first　increased　and　then　decreased.　When　the　ratio　of　torsional　impact　load　to　axial　static　load　was　1.0,　the　penetration　depth　of　the　drilling　cutter　reached　a　maximum.　When　the　torsional　impact　frequency　was　40　Hz-100　Hz,　the　penetration　depth　decreased　with　the　increase　of　the　frequency,　but　the　diameter　of　cuttings　became　smaller　and　smaller,　which　was　conducive　to　cleaning　the　wellbore　with　drilling　fluid.　The　latter　has　the　highest　rock-breaking　efficiency　compared　with　triangular,　sine,　and　rectangular　waves.　Finally,　suggestions　are　given　on　how　to　adjust　these　parameters　by　adjusting　engineering　parameters　and　tool　structure　parameters　to　optimize　the　efficiency　of　the　torsional　percussive　drilling　tool.