Microgrid system, as the carrier of control strategy, can provide verification platform for the research. This paper discusses the control strategy firstly. And then an integrated microgrid system with multi-microgrid structure, containing a variety of distributed generations, energy storage systems, diesel generator and adjustable loads, is introduced. The control strategy of the microgrid system which adopts master-slave control strategy is discussed in detail. The result shows that the mircogrid system using control strategy proposed in this paper can transfer flexibly between grid-connected and islanded mode. This system is able to work well with operation control and other related technologies.