Abstract: Accurate identification of interference source types and intuitive description of power quality management demands are the keys for electric utilities to carry out new business of“basic+value-added”paid power quality. This paper proposes an interference source type identification method and a power quality demand portrait technology based on the maximum mutual information. Firstly, based on the correlation between the user’s power consumption characteristics and power quality characteristics, an interference source type identification method based on the maximum mutual information is proposed. Secondly,based on the power quality monitoring data, a complete set of demand portrait tag system is constructed, which provides a data basis for the research of power quality demand portrait technology of interference sources. Finally, a unified quantitative method for the characteristics of power quality emission level and comprehensive power consumption level is proposed, and the diagram of comprehensive power consumption level and power quality emission level is constructed, which realizes the intuitive description of the power quality management demands of the interference sources. The correctness and effectiveness of the proposed method are verified by using the measured data of a large eastern city of China and the experimental platform of doubly-fed wind turbine.