Abstract: In response to the major challenges faced by green and low-carbon energy transition of China toward the dual carbon targets, the Energy Internet uses transboundary thinking to break through various barriers in the energy system and find potential resources outside the power industry at low cost, which helps the construction of the new power system dominated by renewable energy. There are three dimensions of key elements in the application of transboundary thinking of Energy Internet: green, low carbon, security, efficiency and high quality as the target dimension, the transboundary between departments, agents and industries as the object dimension; the energy layer, information layer and value layer as the solution dimension. The energy layer breaks the physical barriers to realize the interconnection of complementary resources, the information layer breaks the information barriers to create flexible and collaborative wisdom, and the value layer breaks the value barriers to build a win-win ecology. The three dimensions of key elements of transboundary thinking for some Energy Internet projects implemented in China are analyzed.Finally, the scientific problems and key technologies in several directions of interdisciplinary integration in transboundary thinking on the academic level are discussed.