In order to meet the requirements of microgrid system monitoring and energy management, firstly, the hierarchical control of microgrid system is studied. Hierarchical control consists of 3 logical levels: coordination and optimization layer, SCADA and algorithm control layer, equipment layer. On this basis, this article discussed the main function of Microgrid Monitoring and Energy Management Software (EMMS) in the coordination and optimization layer in detail. Secondly, illustrate that using Particle Swarm Optimization(PSO) to realize Energy management optimization function of EMMS, and EMMS coordinating subordinate equipment together to achieve stable frequency and voltage, the switching of off-grid and on-grid operation of microgrid. Finally, this paper constructed the experimental platform and algorithm to prove its main functions.