Abstract: Array magnetotelluric sounding is one of the most promising techniques in regional geophysical investigation. In consideration of the advantages of foreign developed countries and the basic needs of society, the development of array magnetotelluric sounding in China lacks integral planning and is lagging behind. It is urgent to carry out a magnetotelluric observation plan at the national level. In this paper, we review the current development trend of regional geophysics and the construction status of magnetotelluric network in China and abroad. Furthermore, we put forward the top-level concept and construction plan of the national magnetotelluric datum network and the relevant big data bank, and point out the future development priorities. The implementation of this project will expand a new parameter of regional geophysical survey in our country, and promote constructing the 4D model of physical earth, structural earth and geophysical field, which are of great significance to transform the regional geophysical research paradigm and work mode, and help China's deep earth exploration to move forward all over the world.