In current educational practice, teachers frequently encounter challenges in instructional design, such as resource scarcity, a disconnect between theory and practice, and difficulties in creating innovative learning activities. This paper aims to explore the value proposition and application strategies of Generative Artificial Intelligence (GenAI) in competency-oriented instructional design. It begins by analyzing the framework of competency-oriented instructional design, and by using the instructional design of a high school Information Technology lesson on “Image Encoding” as a case study, the paper elaborates on the value and application strategies of GenAI functioning as an “Intelligent Designer” “Innovation Optimizer” and “Detail Refiner” in crafting competency-oriented instructional plans. The objective is to assist educators in leveraging GenAI more effectively to support competency-oriented teaching design, and to emphasize the importance of human–AI collaboration, thus providing references for teachers on integrating GenAI into their instructional design processes.