Abstract: For a domestic 680-thousand-ton-per-year coal-to-olefin project, by verifying the composition and consumption of energy consumption, analyzing the energy transmission losses and the situation of waste heat and residual energy recovery, analyzing the enterprise's energy balance relationship, calculating the comprehensive energy consumption of the project and the comprehensive energy consumption per unit product, evaluating the energy efficiency level and the actual operation situation, the weak links and prominent problems in energy utilization are identified. Specific suggestions for energy-saving retrofitting are put forward from the aspects of the production process, technical equipment, system optimization, operation management, etc., and the expected energy-saving effects, economic benefits, and social benefits of various retrofitting measures are comprehensively evaluated.