At present, most traditional distribution systems adopt special distribution services framework, often only for the characteristics of multimedia applications with a single provision. However, the existing framework cannot provide service guarantee for group-multimedia communication. To solve this problem, this paper designed to work on a new service multimedia group-communication system architecture. Compared with single system using the traditional architecture, the system can simultaneously achieve pictures, video and real-time streaming and other types of distribution service. It leaves out repeat system development and saves the system maintenance overhead. Meanwhile, incorporating this overlay multicast theoretical results, distinct service-quality assurance mechanisms are designed for group multimedia services to improve performance and stability.