The　gear　is　one　of　the　important　parts　of　a　rotary　gearbox.　Once　catastrophic　gear　failure　occurs,　it　will　cause　a　great　threat　to　production　and　life　safety.　The　crack　is　an　important　failure　factor　causing　changes　in　time-varying　stiffness　and　vibration　response.　It　is　difficult　to　effectively　identify　the　vibration　response　and　meshing　stiffness　changes　when　there　is　a　fine　crack　in　the　gear.　Therefore,　it　is　of　great　importance　to　improve　the　accuracy　of　meshing　stiffness　calculation　and　dynamic　simulations　under　micro-cracks.　Investigations　of　meshing　stiffness　and　the　vibration　response　of　a　gearbox　is　almost　all　about　fixed　gear　shape　parameters.　However,　the　actual　production　process　of　gear　system　needs　to　change　gear　shape　parameters.　In　this　paper,　the　meshing　stiffness　and　vibration　response　of　the　dynamic　simulation　signals　of　gear　teeth　with　different　crack　depths　at　different　tooth　shape　parameters　(the　pressure　angle,　the　modulus,　and　the　tooth　number)　were　calculated,　respectively.　The　influence　of　cracks　on　the　vibration　response　was　investigated　by　the　fault　detection　indicators,　the　Root　Mean　Square　(RMS),　the　kurtosis,　and　the　crest　factor.　The　result　shows　that　when　the　pressure　angle　and　modulus　change,　the　vibration　response　changes　erratically.　However,　when　the　tooth　numbers　change,　the　vibration　response　changes　regularly.　The　results　could　be　a　guide　for　choosing　gears　in　different　shape　parameters　when　system　stability　is　the　aim.