Aiming at the problems that gatekeeper for video communication(called VCGK or Video Gatekeeper) can not support greater network scale and has the lower access efficiency in multi-zone, we study and analyze routing technology for largescale video softswitch from multi-zone and hierarchical system framework. We research on designing routing architecture reasonably, importing distributed agent technology and delaminating routing framework based on policies. By using TRIP protocol for communication between agents, we deal with the update and broadcasting of call routing information concentratedly, converge routing info, predigest routing process, and solve the key problems of call control and connection control about real-time video communication. Considering routing QoS and network load balance, we put forward a dynamic routing transfer policy based on distributed routing agent. Finally this paper forms an economical and effective call routing addressing solution which can meet the requests of next generation largescale multimedia video communication network, and solve the difficulty of location in H.323 system appropriately. It can help to enlarge the scale of video communication network based on H.323 protocol.