The invention discloses an underwater sensor network localization method based on triangular distance estimation, and belongs to the technical field of underwater wireless sensor networks. The underwater sensor network localization method is characterized by comprising the following steps: broadcasting, by an anchor node, coordinate information; receiving, by an unknown node, the information of the anchor node to establish a local storage list and storing relevant information; when the unknown node has information of three or more reference nodes, implementing localization of the unknown nodevia a projection technology; when the information of the reference nodes of the unknown node is insufficient, estimating distances of two hops of the reference nodes via triangular distances to increase the number of the reference nodes, and when the number of the reference nodes meets a localization requirement, performing the localization via the projection technology; and upgrading a node thatis localized successfully and has a high trust value into the reference node to assist the localization of other nodes. The underwater sensor network localization method is a three-dimensional distributed type localization method; and an experiment proves that the method has a relatively high node localization coverage rate and a relatively small localization error.