Microgrid integrates the advantages of power generation from new energy and renewable energy-distributed generation effectively and provides a new way for large scale new energy and renewable energy power generation systems connected to the grid. Microgrid can not only enhance the comprehensively cascaded utilization of energy， but also can be used as an effective complementary network of the utility in order to improve the power supply reliability and power quality. Microgrid is becoming one of the most up-to-date and important topics in the field of power systems all over the world. A detailed description on the definition and the basic structure of microgrid is given. The basic operation modes and control strategies for microgrid are presented. This paper analyzes the typical model projects of microgrid all over the world. Finally， the current research and research trends for microgrid in China are summarized， and the concept of building the microgrid with Chinese characteristics considering China's actual conditions is discussed. The related research programs which should be carried out for microgrid are given as well.