The diversification of electricity selling way in the internet environment has put forward new requirements for the construction and management of electricity selling channels. In order to improve overall service level of electricity selling channels, massive scale of the selling big data in a certain area for several years are combined to analyze operation and management process of electricity selling channels concretely. Firstly, referring to the thought of balanced scorecard, an evaluation indicator system reflecting service ability, efficiency, quality as well as potential is constructed. Furthermore, on the basis of indicators causality analysis, a system dynamics evaluation and analysis model is also constructed. Finally, according to the whole sample data of electricity selling and service monitoring data in the area from 2015 to 2017, this paper evaluates the electricity selling channels and uses sensitivity analysis to find the key indicators to simulate the advancement of service level of electricity selling. The suggestions on improvement of service level of electricity selling channels are pointed out. This work is supported by National Key Research and Development Program of China (No. 2017YFB1201000).