A microgrid includes many kinds of microsources， such as photovotaic（PV）， wind turbine generator（WTG）， mocroturbine generator（MTG）， etc.， with different characteristics. The mathematical models and simulation models of these 3 typical microsources are built， and the operation features of different microgrids with single microsource are analyzed on the platform of MATLAB Simulink， based on which different dynamic response characteristics of different microsources are obtained. The operation characteristics of microgrids with all the 3 microsources are studied， and various operation conditions and disturbances are considered during the simulation， such as disconnection from the distribution power grid， load changes in the islanded mode， etc. Further more， different microsources have different influences on the voltage level of the microgrid， e.g. there is an optimal capacity for MTG， which corresponds to the minimum voltage drop percentage of the microgrid from connected to islanded mode. The optimal capacity is an important basis for the microsources capacity configuration during the planning stage of microgrid.