In recent years, multimedia technology and data communications technology has developed rapidly. Multi-party audio and video call is becoming popular. Multi-party audio and video call can solve the problem of long-distance communications. However, the existing call system does not combine the centralized and distributed media flow control modes effectively, which fails to give full play to the advantages of the two control methods. This paper presents a multi-party call dynamic control technology. It takes the client network bandwidth and the number of users as the transformation condition. And through the combination of star topology and mesh topology, the multi-call system can adaptively adjust the distribution method of media flow. Based on SIP conference control the system uses WebRTC technology to improve call quality. The experimental results show that the technology can effectively show the congestion and resource occupancy rate of each client in the system, and adjust the system media flow control in a timely manner, so that the media stream can be transmitted smoothly and call quality can be improved.