The method of establishing a multicast data channel in a network virtualization system includes: creating, on a controller, a virtual remote logical interface for an external interface of a remote node; generating, a multicast tree tunnel that uses a core node as a root, and obtaining a multicast protocol packet sent by a device outside the network virtualization system; acquiring, a multicast source address and a multicast group address from the multicast protocol packet, and generating a multicast forwarding table; searching, the multicast forwarding table for an external interface of the core node, searching for an outbound interface of the multicast tree tunnel on the core node according to the multicast tree tunnel, and generating a P2MP PW forwarding table of the core node, and sending the P2MP PW forwarding table of the core node to the core node. The method implements a multicast service in a virtual cluster router.