In order to find the inherent development law of smart grid under various conditions and make a better coupling of all kinds of smart grid research, the internal mechanism of smart grid development is studied. On the basis of domestic and international smart grid theoretical research and construction practices, starting from the analysis of basic power grid mode, combining with the external drive for smart grid from economic and social aspects, a development mechanism analysis methodology is put forward which considers the factors both inside and outside of power system. Furthermore by use of the methodology, the vision and characteristics of smart grid, development planning and evaluation of the key technologies are analyzed summarily. Some new knowledge from the perspective of smart grid development mechanism and working methods to further deepen the related research are obtained.