In　order　to　reduce　blasting　vibration　reasonably　and　determine　the　damage　range　of　single　hole,　it　is　necessary　to　study　the　impact　pressure　changing　law　of　different　bore　diameters.　By　analyzing　the　movement　process　of　the　hole　wall　under　the　action　of　detonation,　a　simplified　calculation　model　for　three　stages　of　dynamic　expansion　of　the　incompressible　fluid,　rock-breaking,　and　dynamic　expansion　of　the　hole　wall　under　the　action　of　the　explosive　shock　wave　is　established,　and　the　time　history　subsection　function　of　the　hole　wall　pressure　in　each　stage　is　determined.　Based　on　the　ideal　gas　expansion　equation,　the　theoretical　amplification　factor　of　peak　pressure　on　the　bore　wall　is　determined,　the　stage　characteristics　of　bore　wall　pressure　change　were　mathematically　unified,　and　the　impact　pressure　characteristic　curves　of　impact　pressure　on　the　bore　wall　of　blasthole　coupling　charge　were　obtained.　Based　on　LS-DYNA　numerical　simulation　software　and　field　industrial　model　test,　the　calculation　model　results　were　compared　and　validated　by　numerical　analysis　and　super-dynamic　strain　test　model　test.　The　impact　pressure　curves　of　five　different　pore　diameters　(51−200　mm)　under　the　coupled　charge　condition　were　obtained,　and　the　theoretical　amplification　coefficient　of　the　peak　pore　pressure　was　verified　by　experiments.　The　theoretical　model　error　is　controlled　between　0.7%　and　6.4%.　The　comparison　and　analysis　of　theoretical　calculation,　historical　point　of　numerical　analysis,　and　measured　point　data　of　model　test　under　two　specific　conditions　of　76　and　90　mm　show　that　the　theoretical　piecewise　function　can　effectively　fit　the　data　of　numerical　analysis　and　model　test.　The　error　of　peak　pressure　is　6.8%　and　4.9%,　and　that　of　time　is　7.6%　and　4.8%,　respectively.　©　2023　Explosion　and　Shock　Waves.　All　rights　reserved.