Multicast and MPLS are two complementary technologies. Merging these two technologies where multicast trees are constructed over MPLS networks will enhance performance and present an efficient solution for multicast scalability and control overhead problems. In this paper1 , we present a simulator for multicast routing over an MPLS network where we choose PIM-SM (source specific tree) as the multicast routing protocol. A simulator for multicast routing over MPLS network is an original idea since this kind of simulator never existed before and it will help researchers to simulate and evaluate their MPLS multicast related techniques.