Network topology system for transmitting mixed multimedia signal and method thereof

A network topology system for transmitting a mixed multimedia signal and a method thereof are provided. By downloading an index server list which comprising at least identification of index server rely on a manager server and downloading a node server list which comprising at least identification of node server rely on an index server by a first client, a node sever start an agency service by a service information which is received form the index server after the first client connects to the node server by the identification of the node server, mixing a first multimedia signal which is sent from the first client and a second multimedia signal which is sent from a second client by the agency service, and transmitting the mixed multimedia signal to a third client, the system and the method can therefore solve the problem that there is no suitable network topology for transmitting the mixed multimedia signal, and further achieve the effect of expanding servers in the network topology.