In　this　work,　the　characteristics　of　the　exothermic　reaction　between　ammonium　nitrate　and　sulfide　ores　were　explored　using　COMSOL　Multiphysics.　This　reaction　can　cause　an　increase　in　temperature　within　the　blast　holes　of　sulfide　mines　and　can　potentially　induce　premature　explosions　of　the　explosives.　Initially,　simulations　were　conducted　to　observe　temperature　variations　in　blast　holes　before　and　after　the　loading　of　explosives.　Then,　the　impact　of　blast　hole　diameter　and　initial　temperature　on　the　thermal　environment　was　assessed.　Subsequent　analysis　focused　on　the　fluid　field＇s　dynamics,　examining　flow　rate　changes　and　the　concentration　of　signature　gases　produced　by　the　reaction.　Additionally,　the　influence　of　blast　hole　diameter　on　these　parameters　was　evaluated.　The　results　show　that　the　blast　hole　temperature　is　positively　related　to　its　diameter　and　initial　temperature.　When　the　diameter　of　the　blast　hole　is　120　mm　and　165　mm,　a　significant　change　in　flow　rate　is　observed,　with　a　trend　of　being　rapidly　increased　and　then　rapidly　decreased.　The　production　of　NH3　is　always　found　to　be　greater　than　that　of　the　other　two　gases.　As　for　NO　and　SO2,　their　production　is　characterized　by　an　approximate　ratio　of　1:2.　The　numerical　simulation　results　can　provide　important　theoretical　guidance　for　the　spontaneous　detonation　of　blast　hole　in　sulfide　mines.