In order to improve the efficiency and reliability of the microgrid， a multi-agent based control framework is presented. Then， a three-layer multi-agent control system， including main grid agents， microgrid agents and component agents， is established. Accordingly， the special functions and control strategies of each agent are discussed in detail. A simulation example of a particular microgrid based on the multi-agent system（MAS） is performed to demonstrate that the efficiency and reliability of the microgrid can be improved by using MAS.