Abstract: First of all, this paper analyzes the demand of current distribution network planning, and describes the importance of inclusion of the flexible load resources into planning. Furthermore, the classification methods and results of flexible load are proposed from three aspects, i.e. energy interaction mode, scheduling response mode, user and equipment type. Then, aiming at the influence of flexible load access on the distribution network planning, the adaptability and shortcomings of the existing planning methods are analyzed from four aspects, including load forecasting, power balance, planning optimization and planning evaluation,and corresponding improvement ideas and suggestions are put forward. Finally, the new key technologies such as flexible load modeling, big data mining and application are summarized, and the future development of distribution network construction is summarized and prospected.