A group communication system, comprising a base station, a packet control function module, a packet data service node and an authentication, authorization, accounting server, the system further comprising: multiple accessing terminals (15,16,17,18), being adapted to initiate a service request of group talk, or respond a request of establishing group talk service; a group dispatching server, being adapted to provide centralized control of group talk service, establish group talk service in the group for the accessing terminal, and implement the group talk service procedure including group user authentication and transmission of voice service packages; and a group dispatching user side, being an accessing gateway of the group communication system, being adapted to provide signaling and service link between the base station and the group dispatching server, the group dispatching server further including an authentication module, being adapted to authenticate the accessing terminal which makes the service request of group talk; characterised in that the system is based on CDMA2000 high-rate packet data network and further has a buffer mechanism, being adapted to buffer the voice service packages transmitted by forward channel and reverse channel of the group communication system, and said group dispatching server further includes: an arbitration module, being adapted to arbitrate the start-calling priority between multiple groups that make the service request of group talk and the talking priority between the multiple accessing terminals in the group which implement the group talk; a calling establishing module, being adapted to send group talk establishment to other accessing terminals in the group which implement the group talk, and request the base station to allocate aerial resource and finite-side resource for the accessing terminals which implement the talk; and a copying and distributing module, being adapted to copy the voice service packages from the base station and distribute the voice service packages to other accessing terminals in the group which implement the group talk through the allocated resources. multiple accessing terminals (15,16,17,18), being adapted to initiate a service request of group talk, or respond a request of establishing group talk service; a group dispatching server, being adapted to provide centralized control of group talk service, establish group talk service in the group for the accessing terminal, and implement the group talk service procedure including group user authentication and transmission of voice service packages; and a group dispatching user side, being an accessing gateway of the group communication system, being adapted to provide signaling and service link between the base station and the group dispatching server, the group dispatching server further including an authentication module, being adapted to authenticate the accessing terminal which makes the service request of group talk; characterised in that the system is based on CDMA2000 high-rate packet data network and further has a buffer mechanism, being adapted to buffer the voice service packages transmitted by forward channel and reverse channel of the group communication system, and said group dispatching server further includes: an arbitration module, being adapted to arbitrate the start-calling priority between multiple groups that make the service request of group talk and the talking priority between the multiple accessing terminals in the group which implement the group talk; a calling establishing module, being adapted to send group talk establishment to other accessing terminals in the group which implement the group talk, and request the base station to allocate aerial resource and finite-side resource for the accessing terminals which implement the talk; and a copying and distributing module, being adapted to copy the voice service packages from the base station and distribute the voice service packages to other accessing terminals in the group which implement the group talk through the allocated resources. an arbitration module, being adapted to arbitrate the start-calling priority between multiple groups that make the service request of group talk and the talking priority between the multiple accessing terminals in the group which implement the group talk; a calling establishing module, being adapted to send group talk establishment to other accessing terminals in the group which implement the group talk, and request the base station to allocate aerial resource and finite-side resource for the accessing terminals which implement the talk; and a copying and distributing module, being adapted to copy the voice service packages from the base station and distribute the voice service packages to other accessing terminals in the group which implement the group talk through the allocated resources.