Recently,　the　development　of　the　Internet　of　Things　(IoT)　provides　plenty　of　opportunities　and　challenges　in　various　fields.　As　an　essential　part　of　IoT,　machine-to-machine　(M2M)　communications　open　a　novel　way　that　the　machine-type　communication　devices　(MTCDs)　are　connected　and　communicated　without　any　human　intervention.　Meanwhile,　delay-tolerant　data　play　an　important　role　in　M2M　communications-based　IoT,　and　it　puts　more　emphasis　on　powerful　data　caching,　computing,　and　processing,　as　well　as　the　security　and　stability　of　data　transmission.　To　meet　these　requirements　in　M2M　communications　networks,　in　this　article,　we　introduce　some　promising　technologies,　such　as　edge　computing　and　blockchain,　and　propose　a　joint　optimization　framework　about　caching,　computation,　and　security　for　delay-tolerant　data　in　M2M　communications　networks　based　on　dueling　deep　Q-network　(DQN).　According　to　the　dynamic　decision　process　by　DQN,　the　optimal　selection　and　decision　of　caching　servers,　computing　servers,　and　blockchain　systems　can　be　made　to　achieve　maximum　system　rewards,　which　includes　higher　efficiency　of　data　processing,　lower　network　costs,　and　better　security　of　data　interaction.　Extensive　simulation　results　with　different　system　parameters　show　that　our　proposed　framework　can　effectively　improve　the　system　performance　for　blockchain-enabled　M2M　communications　compared　to　the　existing　schemes.