Boulder　is　a　kind　of　weathered　rock　residue　with　high　hardness　and　strength,　which　is　one　of　the　most　harmful　problems　to　shield　machine.　Based　on　the　interval　between　Pengcuo　north　station　and　Caicuo　station　of　Xiamen　rail　transit　line　4,　this　paper　analyzed　the　stability　of　shield　tunneling　in　the　coastal　boulder　stratum　by　discrete　element　method,　and　studied　the　influence　of　the　distance　between　the　boulder　and　the　tunnel,　the　buried　depth　of　the　tunnel,　the　location　of　the　boulder　and　the　gap　between　the　shield　tail　on　the　stability　of　the　stratum.　The　results　show　that　with　the　increase　of　the　distance　between　the　boulder　and　the　tunnel,　the　disturbance　range　of　the　stratum,　the　change　of　the　lining　pressure　of　the　arch　crown　and　the　settlement　of　the　earth’s　surface　all　decrease.　With　the　increase　of　the　depth　of　the　tunnel,　the　disturbance　range　of　the　stratum　and　the　settlement　of　the　ground　decrease,　and　the　earth　pressure　of　the　lining　increases　as　a　whole.　With　the　location　of　the　boulder　gradually　away　from　the　top　of　the　tunnel,　the　disturbance　range　of　the　stratum　and　the　settlement　of　the　earth’s　surface　are　decreasing.　With　the　increase　of　the　gap　at　the　tail　of　shield　and　the　increase　of　the　ground　settlement,　the　earth　pressure　on　the　lining　vault　increases.　©　2021,　Central　South　University　Press.　All　rights　reserved.