This report provides a comprehensive overview of 3D User Interfaces (3D UI), examining their introduction, technological components, design elements, and practical applications. It delves into the relationship between 3D UI and various fields like human-computer interaction, space sensing, and cognitive psychology, highlighting the use of 3D UI in video gaming and other industries. The report outlines the two main categories of 3D UI study: technology and design components, detailing the input/output devices, interaction proficiency, and design elements like 3D widgets and scenarios. It explores practical applications in areas such as real-world metaphors, information visualization, simulation shows, and 2.5D UI, including potential applications in the healthcare sector. The report also discusses the benefits of 3D UI, such as improved information visualization, scenario context, and interactive experiences, while acknowledging potential drawbacks and risks. The report concludes by emphasizing the potential of 3D UI to revolutionize various sectors and the importance of understanding its complexities for future development.