Abstract: This paper introduces the characteristics of total site integration technology. With a real case of oil refining enterprise and SuperTarget software, the method was introduced in detail and optimized. The theoretical optimal utility configuration, total site pinch position, the direction of the utility level optimization, potential heat and power co-generation, and the potential of the processes and utilities combination optimization were investigated. Guided by the above analysis, energy system optimization of the sample refinery was implemented. The energy saving of 31.4 MW is obtained. The application shows that the technology to guide energy system optimization of oil refining enterprises has an obvious effect.