With the open competition of electricity market and the increasing demand of people for a better life and high-quality power supply services, the traditional power service has no longer adapted to the current situation. How to provide better service for large power customers has become the focus and highlight of power market competition. Combining economic value, development potential, credit value, social value and other dimensions, a value classification model was built. A customer’s scientific electricity consumption index model was built from the aspects of technical, economic and management energy efficiency of major customers of electric power. Big data technology was used to analyze the user’s various power usage behaviors deeply and comprehensively perceive users’needs and formulate precise marketing strategies. Precise marketing model of“Enjoy+”major customers was proposed to provide diversified, personalized and customized energy services and value - added services for major power customers,and enhance the market competitiveness and economic benefits of the State Grid Corporation.