A very inexpensive receive-only satellite receiver can receive high bandwidth traffic from a feeder. Therefore the connection between the feeder and the receiver is uni-directional. The existing routing protocols, such as Link-State and Distance-Vector, are designed on the premise that any links are bidirectional and they cannot handle the uni-directional links. In this paper,a dynamic multicast routing protocol is proposed, which can handle uni-directional networks. This protocol can also adapt to the dynamic change of the topology of the network and has good scalability. A formal description of the protocol by Petri net is given. Liveness, deadlock free and other properties of the protocol are proved. The connection between the feeder and the receiver is uni-directional. The existing routing protocols, such as Link-State and Distance-Vector, are designed on the premise that any links are bidirectional and they can not handle the uni-directional links. This paper can also handle uni-directional networks. This paper can also handle the uni-directional networks. This protocol can also adapt to the dynamic change of the topology of the network and has good scalability. A formal description of the protocol by Petri net is given. Liveness, deadlock free and other properties of the protocol are proved.