Based　on　original　FEM/DEM　coupling　analysis　method,　a　new　model　for　blast　simulation　is　implemented.　The　model　considers　increasment　of　the　volume　occupied　by　the　gas　and　stable　decrease　in　gas　pressure　with　the　expansion　of　cracks　due　to　the　blast　gas　embedding,　and　also　takes　into　account　the　action　of　gas　on　the　fissures　linked　at　the　explosion　chamber.　The　limitation　is　overcome　in　the　existing　blasting　model　of　FEM/DEM,　where　the　pressure　is　only　applied　on　the　surface　rock　of　blasting　chamber　without　considering　action　of　the　embedded　gas　on　the　newly　generated　cracks.　Meanwhile,　a　novel　search　algorithm　of　fracture　network　is　proposed　by　compiling　a　simple　recursive　function　for　the　search　of　complex　fracture　network;　and　a　very　simple　method　is　used　to　handle　the　complex　problem.　Finally,　a　numerical　example　indicates　that　the　improved　FEM/DEM　can　simulate　crack　initiation　and　propagation　of　stress　waves　during　explosion,　showing　a　great　potential　of　this　method　for　the　blast　simulation.　©,　2015,　Academia　Sinica.　All　right　reserved.