Abstract: Teaching 3D design skills effectively has always been a persistent challenge in engineering education, particularly in professional courses like Mechanical Design．To address lack of interactivity and practicality in traditional teaching methods, a 3D design virtual simulation teaching system based on mixed reality（MR）technology has been developed．By integrating real physical environments with digital information, system built a highly interactive and immersive learning environment．Designed with user at core, system prioritized usability, interactivity, and applicability, and integrated key technologies such as collision detection, virtual disassembly, and touchscreen interaction．Applied in 3D design course, system has significantly enhanced students’ spatial perception, innovative design abilities, and learning enthusiasim, while helping teachers to realize real-time monitoring and targeted guidance．User feedback and evaluation results demonstrated that system not only optimized teaching processes and improved teaching effectiveness, but also offered valuable theoretical and practical insights for innovating 3D design teaching models in higher education．