A routing method is used to establish a data transfer path between a source node and a destination node in wireless networks having a tree structure. If a relay node relaying a data transfer receives data to be forwarded from a source node to a destination node, the routing table is searched to check whether the routing table stores information on a path to the destination node, and the received data is forwarded along a corresponding path if the path information to the destination node exists. However, if the information on a path to the destination node does not exist in the routing table, the routing table is searched to check whether the routing table stores information on a path to a parent node of the destination node, and; if the path information exists, the received data is forwarded along the path to the parent node.