Abstract: With the expansion of the construction scale of the power grid and the promotion of digital economy, the digitalization and intelligence of the power grid have become an urgent need for the development of the power industry. Digital twin (DT) technology, which is based on information technology system such as digital identification, automated sensing, networked connection, inclusive computing, intelligent control, and platform services, provides new ideas and approaches for promoting safe and stable operation of power grid and building energy internet enterprises. In this paper, based on the concept, basic structure, and characteristics of DT, the connotation of the DT power grid was proposed, the framework of the DT power grid was constructed, the operation mode of DT power grid was introduced, and the key technologies of DT power grid was analyzed. Moreover, typical applications including equipment layer, power grid layer, business layer and operation management layer were proposed. The research provides theoretical support for the construction of DT power grid, and guides the development direction and construction ideas for DT power grid.