In the context of the release of the power-selling side, the sales companies established by various investment entities are increasingly participating in the competition in the electricity sales market. Therefore, how to effectively control the power customer resources will become an in-depth study of the power sales companies. The key issue. In view of this, this paper carries out a comprehensive evaluation study on the viscosity of power customers for power sales companies. Firstly, the meaning of power customer viscosity is clarified, and then the important factors affecting the viscosity of power customers are analyzed. Secondly, the electricity customer viscosity evaluation index system of the sales company is established from four aspects: customer behavior, customer perception, customer dependence and customer trust. The fuzzy comprehensive evaluation method is used to construct a comprehensive evaluation model. Finally, the representative of a typical sales company in a certain region is selected to carry out a case study. The results of the example show that the evaluation model proposed in this paper is effective and improves the service quality and long-term development for the sales company. It is of great significance.