Abstract: In order to cope with the increasingly severe climate change problem, China has put forward the strategic target of emission peak and carbon neutrality, which has drawn a grand blueprint for the national climate governance and energy low-carbon transformation. The reduction of carbon emission and increase of carbon sink are two important ways to achieve the "double carbon" target, which, however, are difficult to attain due to the restrictions of policy, space, technology and other factors. As a kind of territorial resource with broad development prospects, underground space can provide a stable and sufficient space support for the reduction of carbon emission and increase of carbon sink. First, the low-carbon potentials of underground space were revealed based on its functional characteristics. Then, the concept of underground-space-supported future electric energy system was proposed. Finally, the future research and the key problems to be solved were proposed.