Microgrids as an important form of distributed renewable energy integration, have garnered significant attention due to their flexibility and efficiency. the fundamental concepts, functional characteristics, and developmental trends of microgrids are revieved systematically. Key operational control strategies for grid-connected, islanded, and transition modes are analyzed in detail, with a focus on the critical role of energy management systems in achieving stable operation, economic scheduling, and energy optimization. In grid- connected mode, optimization models are developed to enhance renewable energy utilization and absorption efficiency, while in islanded mode, centralized and distributed control strategies work collaboratively to maintain system frequency and voltage stability. By integrating existing technical standards, the main challenges of microgrid operation control are identified. Future development suggestions are proposed in the areas of standardization, management modes, and economic improvements, providing valuable insights for the further advancement of microgrid technologies.