Based　on　the　theory　of　discrete　element　method,the　particle　contact　model,the　particle　contact　search　algorithm　and　the　iteration　time　step　algorithm　in　the　analysis　process　are　improved,and　the　force　of　the　tooth　roll　in　the　crushing　process　is　analyzed　to　ensure　that　the　strength　and　life　requirements　are　met.　The　improved　discrete　element　method　is　used　to　simulate　the　crushing　process　of　the　first　rough　crushing　section　of　the　double-tooth　roller　crusher.　Firstly,the　discrete　element　method　is　used　to　simulate　the　crushing　process　of　coal　particles　by　the　double-tooth　roller　crusher,and　the　crushing　force　of　the　double-tooth　roller　crusher　is　obtained.　The　results　are　compared　with　the　solution　calculated　by　the　traditional　empirical　formula.　The　simulation　results　under　different　parameters　were　analyzed,and　the　influence　of　the　speed　and　particle　diameter　of　the　tooth　roll　on　the　crushing　force　was　studied.　Then,combined　with　Hertz-Mindlin　non-　sliding　contact　model　and　Hertz-Mindlin　bonding　contact　model,the　particle　contact　model　is　simplified　to　vibration　motion　model　and　the　calculation　formulas　of　each　component　force　are　derived　respectively.　On　the　basis　of　EDEM　software,the　second　development　was　carried　out,and　the　coal　particle　contact　model　combined　with　the　two　models　was　constructed　by　API　plug-in.　Before　entering　the　crushing　chamber,coal　particles　are　transformed　into　compact　aggregates　of　several　small　particles,and　bonding　contacts　are　exerted　between　the　small　particles.　When　the　external　force　between　any　two　small　particles　is　less　than　the　binding　constraint　force,the　relative　displacement　between　the　small　particles　is　neglected,so　that　the　particle　set　still　moves　in　a　whole　shape.　When　the　external　force　between　two　small　particles　is　greater　than　the　binding　force,the　binding　constraint　between　the　two　small　particles　is　cancelled　to　separate　the　small　particles　from　the　aggregate.　The　contact　model　of　coal　particles　established　by　this　method　can　effectively　simulate　the　complete　crushing　process　of　coal　particles,and　save　computing　time　and　resources.　Finally,through　comparative　analysis,the　optimal　value　of　contact　retrieval　mesh　size　used　in　numerical　simulation　of　double　tooth　roll　crusher　is　obtained.　Taking　YLWP+S1000-1500WX　double-toothed　roller　crusher　newly　designed　and　manufactured　as　an　example,the　influence　law　is　studied.　The　crushing　process　of　coal　-fired　particles　is　simulated　by　the　above-mentioned　theoretical　method,and　the　force　change　curve　of　crushing　teeth　in　the　crushing　process　is　extracted.　The　maximum　crushing　force　load　and　average　crushing　force　load　of　single　row　crushing　teeth　on　the　first　rough　crushing　roll　in　the　process　of　crushing　normal　coal　particle　are　obtained,and　the　influence　law　of　particle　diameter　and　rotational　speed　of　gear　roll　on　the　force　of　crushing　teeth　is　obtained.　It　provides　a　reference　for　the　design　of　crusher　and　the　prediction　of　crushing　capacity.　©　2020　China　Coal　Society.　All　rights　reserved.