Arch bridges are important bridge types for mountain railways due to their high structural stiffness and spanning capacity. In the construction of the Xijiang Grand Bridge on the Nanning-Guangzhou High-Speed Railway, facing technical blanks, we conducted systematic research on the technical problems existing in the design, construction, and operation of high-speed railway long- span steel box arch bridges. Through theoretical and experimental research, the key technical parameters of high-speed railway long-span steel box arch bridge are proposed, the arch rib structure is innovatively designed, a new arch bridge foundation structure that can bear huge horizontal thrust in the broken rock lay- er is pioneered, a new method of wind-induced vibration control of long-span steel box arch bridge is developed, the temperature deformation mechanism of the arch rib is revealed, and the fine adjustment technology of the track on the bridge is proposed, forming a complete set of construction technology for the long-span steel box arch bridge in complex and difficult mountainous areas.