A method, a wireless communication system, and a group mobility controller (GMC) for processing group mobility are provided by the exemplary embodiments of the present invention. In the method, a fixed GMC paging group identifier (PG-ID) is assigned to the GMC when the GMC starts up a group mobility function; and a target network obtains group information of the GMC, and updates a PG-ID list of the target network with the group information of the GMC during a message interaction process when the GMC hands over from a serving network to the target network, and then utilizes the updated PG-ID list during a subsequent interaction process with a group node. The system includes a GMC, a serving network, and a target network. The signaling storm raised when numbers of terminals in an idle mode perform location update at the same time during the group mobility can be avoided according to the above technical solutions, thereby realizing the economy of air interface resources and signaling overheads.