Abstract: A method of generating relay paths among a plurality of participants in multi-transmission is provided for transmitting predetermined data to the participants. The method includes a first step of analyzing access paths of the participants; a second step of generating a binary tree structure of relay paths among participants belonging to each subnet group; a third step of arranging gateways on the access paths of the participants according to the order on a connection path connecting the gateways to a data server; a fourth step of classing gateways, which are connected to the same upper gateway and are at the same level as a result of the arrangement, as a subordinate set of the upper gateway; and a fifth step of calculating the number of hops of each gateway within the subordinate set to a corresponding subnet group and generating a binary tree structure of relay paths starting from a gateway having relatively fewer hops toward a gateway having relatively more hops.