A multicast service of a 3GPP Universal Mobile Telecommunications System (UMTS) is disclosed. A multicast service stream identifier is provided so that each multicast area can receive different information for one service or one multicast service can be provided with different QoSs to areas. In addition, the multicast service stream identifier is provided which can selectively receive diverse menus or channels for one multicast service provided in the same area. Thus, by providing the multicast service stream identifier, users' desires for various services can be satisfied.