The energy benchmark has been recognised as an effective analytical methodology and management tool that help to improve the efficiency and performance of energy utilisation. With a wide distribution and large amount of energy consumption at a low efficiency, machining systems have considerable energy-saving potential. This paper proposes a task-oriented energy benchmark in machining systems, and illustrates the concept of the task-oriented energy benchmark and indicators. A method for developing the task-oriented energy benchmark considering the certainty production task and the uncertainty production task is proposed, which lays a solid foundation for studying the energy benchmark, benchmark rating system and energy certification. Furthermore, a case study of the task-oriented energy benchmark not only verifies the reliability but the effectiveness for energy-efficient production.