Abstract: Micro electric-grid has complicated structure and needs many functional units for flexible dispatch of power. Due to the lack of detailed national standards on micro electric-grid, so the construction condition limitation, the type, structure, function of each micro electric-grid project are different, it is difficult to embody the completeness of micro electric-grid. Based on a first large-scale demonstration project of new energy application and smart micro electric-grid led by government, the necessary function subsystem for a complete micro electric-grid is discussed from 4 links of power generation, storage, distribution and consumption. A case of micro electric-grid is analyzed to provide technical support for micro electric-grid construction.