The present invention relates to a satellite IP multicasting system and method for constructing an IP multicast network by a unit of internet node having a router for subscriber connection or a switch, and for transmitting a multicasting packet transmitted from a content provider into a local IP multicast network via a satellite. The satellite IP multicasting system features a backbone network, a content provider, a satellite network and a local network. The local network, which is interworked with the backbone network, is configured to multicasting protocol at a router or a switch, performs reverse path forwarding by static multicasting routing setup on a router or a switch connected to the satellite network via Ethernet and on a subscriber router or by IP designation of the same sub-net with source address of IP header of the multicast packet to an output port of a satellite data receiver and a port of a router connected to the satellite data receiver, and transmits the multicast packet into a terminal client.