In this chapter, a digital twin architecture for the traction power supply system of high-speed trains is proposed, aiming to realize the intelligent operation and maintenance of the system. The digital twin architecture consists of a physical layer, a perception layer, a data layer, a computing layer, a functional layer, and an application layer. Based on the industrial Internet platform, the architecture uses data integration and system integration capabilities to realize the collaborative optimization of physical space and virtual space through real-time data perception and two-way interaction. By collecting the information data of the traction power supply system, adopting the multi-scale, multi-physical, multi-spatial and multi-disciplinary cross-integration methods, and using the digital twin computing platform and service platform, the digital twin model of the whole life cycle state of the high-speed train traction power supply system is constructed. Through this technology, the efficient and intelligent management of the power supply system can be realized, including fault prediction, equipment life evaluation and optimal resource allocation, and finally the overall improvement of the operation efficiency and reliability of the traction power supply system can be realized.