The　competition　of　interpersonal　communication　platforms　is　a　complex　process　affected　by　various　factors.　This　paper　aims　to　simulate　and　analyze　this　process　from　a　bottom-up　perspective.　Individual　platform　selection　serves　as　the　micro-foundation　for　the　study.　The　evolution　of　online　interpersonal　communication　networks,　and　innovations　proposed　by　online　interpersonal　communication　platforms,　would　also　impact　this　process　by　affecting　individual　selection　on　those　platforms.　Three　scenarios　were　designed　for　this　study　to　simulate　typical　modes　of　competition.　In　this　regard,　the　simulation　results　were　compared　to　practical　cases.　Taken　together,　this　bottom-up　simulation　model　could　reproduce　and　anticipate　the　applied　competition　process　associated　with　such　platforms.　Based　on　this　model,　it　was　found　that,　in　any　case,　one　online　interpersonal　communication　platform　will　eventually　monopolize　the　market,　either　partly　or　entirely.　The　late　entrant　platform,　comprising　a　major　innovation,　tends　to　fail　when　competing　with　the　incumbent　monopoly　due　to　＂network　externalities.＂　Even　when　two　competing　platforms　continue　to　propose　innovations,　and　they　will　alternately　lead　the　competition　due　to　those　innovations,　this　type　of　replacement　of　their　competitive　positions　in　the　market　may　only　occur　a　few　times　and　then　disappear　completely.