In order to evaluate the microgrid in the planning stage more objectively， for the characteristics of various combinations of microgeneration and flexible operation modes， the microgrid evaluation index is divided into four aspects of reliability， economy， market operation and environmental factors. All of the indicators are described in detail and the tree structure of four aspects is constructed. Combined with practical examples， firstly， a differential evolution algorithm is used to solve the optimization of the objective function， getting a variety of microgrid， and analytic hierarchy process（AHP） is used to give a comprehensive evaluation of the obtained microgrid. In this case， a whole process of the AHP method is illustrated step by step. The case study indicates that the method can avoid the uncertainty of the decision-making factors and the subjectivity of expert evaluation. It is shown that the method is a practical solution for microgrid planning.