The development of new energy generation and energy storage has changed topology of traditional power grid. On the other hand, the development of intelligent technology in buildings has transformed building from single type energy consumers to hybrid energy producers. As a result, the role and function of smart buildings in power grid of carbon neutral has changed dramatically. The definition, composition and connotation of smart buildings under the development of new technologies need to be further clarified and summarized. Firstly, the principle of smart buildings participating in power grids of carbon neutral is discussed. Then,based on the difference in the amount of power generation in buildings, the parallel mode of smart building and power grid is discussed. Lastly, development of future development of power grids and buildings are prospected.