Method for avoiding routing loop by adopting tree topology relationship

The invention provides a method for avoiding a routing loop by adopting a tree topology relationship. A tree network is established, a topology sequence number is distributed to a node, branched topology sequence information is created in the tree network, and the routing loop is avoided in the method. The method comprises the following steps of: broadcasting routing request (RREQ) message by a source node, and searching the branched topology sequence information by the node receiving the RREQ message; judging whether the source node is an ancestor node of the node receiving the RREQ message; if no, responding the RREQ message by the node receiving the RREQ message; and if yes, not responding the RREQ message by the node receiving the RREQ message. The method prevents the possibility of the routing loop by analyzing the topology level relationship among the nodes.