With the rapid development of energy storage systems, DC distribution networks, and high-power-density power electron- ic equipment, isolated bidirectional DC-DC converters have become key interfaces for bidirectional energy conversion. Among various converter topologies, the dual active bridge ( DAB) converter has attracted extensive attention due to its galvanic isolation capability, structural symmetry, and suitability for high-frequency operation. The technical characteristics, research status, and development trends of DAB converters were systematically reviewed. Firstly, various isolated bidirectional DC-DC topologies were compared in the context of global energy transition and the development of DC distribution networks, highlighting the comprehensive advantages of DAB converters in terms of efficiency, power density, and dynamic performance. Subsequently, the key technical challenges encountered by isolated bidirectional DC-DC converters in wide-operating-range applications, high-frequency design, and digital control implementation were summarized, and potential research directions oriented toward engineering practicality and system reliability were discussed. This re- view is intended to provide a useful reference for the design and application of high-performance bidirectional power conversion systems.