A method for establishing a multicast data channel in a network virtualization system, which includes a core node, a remote node and a controller, comprising: creating, on the controller, a virtual remote logical interface for an external interface of the remote node, wherein the external interface of the remote node is an interface used to connect to another network device outside the network virtualization system and the virtual remote logical interface is a logical interface that corresponds to the external interface of the remote node; generating, by the controller, a multicast tree tunnel that uses the core node as a root; obtaining, by the controller, a multicast protocol packet, wherein the multicast protocol packet is a protocol packet sent by a device outside the network virtualization system by using the remote node or the core node of the network virtualization system; acquiring, by the controller, a multicast source address and a multicast group address from the multicast protocol packet; generating, by the controller, a multicast forwarding table according to the multicast source address, the multicast group address, a multicast inbound interface, and a multicast outbound interface, wherein the multicast outbound interface comprises an external interface of the core node and the virtual remote logical interface and wherein the multicast inbound interface is an inbound interface for the multicast protocol packet entering into the network virtualization system and the multicast outbound interface is an outbound interface for the multicast protocol packet departure from the network virtualization system; allocating, by the controller, a point-to-multipoint pseudo wire, P2MP PW, label to the multicast source address and the multicast group address; searching, by the controller, the multicast forwarding table for the 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 point-to-multipoint pseudo wire, P2MP PW, multicast forwarding table of the core node according to the multicast source address, the multicast group address, the P2MP PW label, the multicast inbound interface, the external interface of the core node, and the outbound interface of the multicast tree tunnel on the core node, wherein the outbound interface of the multicast tree tunnel is an outbound interface on the core node for the multicast tree tunnel; and sending, by the controller, the P2MP PW multicast forwarding table of the core node to the core node, so that the core node forwards a multicast data packet according to the P2MP PW multicast forwarding table. creating, on the controller, a virtual remote logical interface for an external interface of the remote node, wherein the external interface of the remote node is an interface used to connect to another network device outside the network virtualization system and the virtual remote logical interface is a logical interface that corresponds to the external interface of the remote node; generating, by the controller, a multicast tree tunnel that uses the core node as a root; obtaining, by the controller, a multicast protocol packet, wherein the multicast protocol packet is a protocol packet sent by a device outside the network virtualization system by using the remote node or the core node of the network virtualization system; acquiring, by the controller, a multicast source address and a multicast group address from the multicast protocol packet; generating, by the controller, a multicast forwarding table according to the multicast source address, the multicast group address, a multicast inbound interface, and a multicast outbound interface, wherein the multicast outbound interface comprises an external interface of the core node and the virtual remote logical interface and wherein the multicast inbound interface is an inbound interface for the multicast protocol packet entering into the network virtualization system and the multicast outbound interface is an outbound interface for the multicast protocol packet departure from the network virtualization system; allocating, by the controller, a point-to-multipoint pseudo wire, P2MP PW, label to the multicast source address and the multicast group address; searching, by the controller, the multicast forwarding table for the 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 point-to-multipoint pseudo wire, P2MP PW, multicast forwarding table of the core node according to the multicast source address, the multicast group address, the P2MP PW label, the multicast inbound interface, the external interface of the core node, and the outbound interface of the multicast tree tunnel on the core node, wherein the outbound interface of the multicast tree tunnel is an outbound interface on the core node for the multicast tree tunnel; and sending, by the controller, the P2MP PW multicast forwarding table of the core node to the core node, so that the core node forwards a multicast data packet according to the P2MP PW multicast forwarding table.