As global energy demands grow and environmental issues intensify, enhancing energy utilization efficiency and promoting sustainable development have become focal points of attention. This paper delves into the optimization and enhancement strategies for energy efficiency indicators in Integrated Energy Systems (IES) based on Integrated Demand Response (IDR). Firstly, a mathematical model for IDR is established. Subsequently, an energy efficiency evaluation index is proposed for IES, which comprehensively considers the acquisition, conversion, storage, and transmission of electricity, gas, heat, and cooling energy within the system. To optimize system energy efficiency, an optimization model for IES is constructed, and the Fruit Fly Optimization Algorithm is selected for solution. Finally, the validity of the proposed model and optimization scheme is verified through a case study of a certain eco-industrial park. The results indicate that the scheduling strategy considering IDR can significantly reduce system operating costs and wind curtailment, increase the proportion and utilization of renewable energy, and substantially enhance the overall energy efficiency of the system.