The present invention provides a method, system and apparatus for an MG to transmit and receive multicast data. A method for an MG to receive multicast data in embodiments of the present invention include the following: the MG receives a multicast-related indication from the MGC, reports the relevant information to the router in the network at the multicast source side according to the indication, and requests to join the multicast group. The MG receives the multicast data transmitted by the multicast source. A method for an MG to transmit multicast data in embodiments of the present invention include the following: the MG receives the multicast-related indication from the MGC; and the MG transmits the corresponding multicast data to the users in the network at the receiver side in the form of multicast according to the indication.