Abstract: In order to deepen the work of promoting national energy conservation and consumption reduction, user-side energy big data is used to establish an accurate assessment model and method for enterprise-level comprehensive energy use efficiency, so as to optimize the energy use efficiency of enterprises. This paper takes equipment manufacturing enterprises as the research object. Firstly, according to the characteristics of the energy composition of such enterprises, the scope of energy efficiency assessment is proposed. The analytic hierarchy process is used to construct the evaluation system of integrated energy efficiency for enterprises. It comprehensively considers the energy efficiency of the company’s economy, energy supply side and energy use side, The system divides the evaluation of integrated energy efficiency for enterprises into five layers. In addition, the combination method of Moody’s chart and entropy weight method is used to calculate the index weights of different levels, and the enterprise comprehensive energy efficiency calculation model is established through the weighting method. Finally, the comprehensive energy efficiency data of different temporal and spatial dimensions were calculated using the on-site data of the enterprises. The analysis of the results verified the effectiveness of the comprehensive energy efficiency assessment system and its method proposed in the paper, and formed guidance for the energy saving and consumption reduction work of enterprises.