This paper focuses on the background of the "Three Teachings" reform and deeply explores the development and practice of the loose-leaf textbook of "Electrical Training". Firstly, it explains the connotation and significance of the "Three Teachings" reform, and points out its key role in promoting educational progress; then it analyzes the existing problems of electrical training textbooks. Next, it details the development process of the loose-leaf textbook, including the content design centered around actual needs and trends, the structural arrangement of flexible combination and convenient update, etc., and uses practical cases to show its remarkable effects and advantages. Finally, it looks forward to its future development trends, such as optimizing the development mechanism, integrating information technology and promoting experience. Generally speaking, this research has important guiding and practical value for the improvement and development of this loose-leaf textbook.