Delay/Disruption Tolerant Network (DTN) is characterized by non-deterministic routing and intermittent connectivity. Hence, some routing protocols in DTN use multiple copy mechanisms to deliver packets, resulting in extensive energy consumption. Many studies have investigated how to reduce the energy cost of copy replication and thus increase the energy efficiency of the network. In this paper, we propose an energy efficiency-based dynamic beaconing strategy (EE-DBS) in DTN. Depending on network state, the node adaptively adjusts beaconing intervals, thereby increasing lifetime without decreasing the transmission efficiency. The proposed mechanism can be applied to any routing protocol in which nodes obtain information about the network state through beaconing. The simulation results show that the proposed mechanism can improve energy efficiency while guaranteeing the network performance, and has excellent adaptability to various routing protocols.