The invention relates to the technical field of computer network streaming media and discloses a method for streaming media data released by combining an IP multicast technology in a P2P network. A user node is added into the P2P network; when the user node belongs to certain multicast island, whether a multicast group exists in the multicast island is judged, and the user node is added into the multicast group after that the multicast group exists in the multicast island is confirmed; and the release of the streaming media data is performed in the P2P network through the IP multicast technology. The method effectively overcomes the defects that the streaming media service fails to be received between multicast islands in a streaming media system based on IP multicast and QoS fails to be guaranteed in a streaming media system based on a P2P technology due to the high dynamics of the node.