Abstract: A layered-depth based routing protocol was proposed for underwater wireless sensor networks (layered-DBR). After nodes broadcast, message only could be received by nodes in predefined depth in order to control the copies of message and finally a network hierarchy model related to redundancy could be built. In this model, the relative depth between nodes and the resident energy of nodes need to be calculated before and after the message forwarding, and then the message forwarding probability can be obtained. A message queue management machanism was established, with which could manage the message's forwarding and history messages, and then the dequeue and enqueue methods were proposed. Compared with DBR and Flooding by simulation, the layered-DBR algorithm can control the network redundancy, reduce the network energy consumption, and prolong the network lifetime.