Abstract: Combining micro-grid construction rules and considering the operation requirements of isolated micro-grids, such as micro-source configuration, sensitive load support, voltage, frequency support, and furthermore, these rules were introduced in the form of grid-construction constraints into the optimization model. For the mass power flow calculation in the process of constructing fitness function of the micro-grids optimization, a hierarchical optimization thought was proposed, which treated the processes that not involved power flow calculation as the first stage, and those involved as the second stage. Only the results that meeting the optimal solution of first stage can continue the second stage, which can reduce the calculation greatly, and obtain accurate optimal solution. The simulation results verify the effectiveness of the model and methods.