High-speed railway system is interdisciplinary subject that covers infrastructure, mobile equipment, traction power supply, communication signal, operation and maintenance, and transportation organization. The purpose of this book is to give readers a basic understanding of the technology behind of China's high-speed rail network. In this book, the author mainly focusses on the innovations of products and processes, especially product innovation, which involves the selection of technology route, technology system and technology source. Therefore, the innovation in HST here refers to the selection of technology route, technology system and technology source, as well as, the new products developed and manufactured according to the selection. With the in-depth study, the author would like to provide outlook for development in this area in the next stage.