High-speed railway has achieved rapid development in China during last decades, along with many scientific and technological challenges. In this presentation, an overview is given on the development of high-speed railways in China, including the history of raising train speed and current status of high-speed railways. Key challenges focusing on dynamics problems are discussed at design stage and at operation stage of Chinese high-speed railways, respectively. Some strategies for coping with the challenges are introduced on the basis of our research work on railway system dynamics, and some application examples are provided to demonstrate their effectiveness in practical high-speed railway engineering.