Abstract: A model of multicast communications is proposed for NoC (networks on chip) to provide communications to guarantee deadlock-free routing. Multicast model has the capability of reducing traffic remarkably, increasing utilization ratio of channels and decreasing testing time in test mode. Modeling of the multicast communications were simulated and applied on 2D Torus NoC. Experimental results demonstrate that our communications model has lower average communication latency and higher throughput than unicast communications.