This article takes the design of the temporary power supply scheme for the construction of two TBMs in the Xinjiang Kashuang Water Transmission Tunnel Project as an example to summarize the planning and layout of the regional substations and the selection of high-voltage power supply modes in the power supply and transformation system of the whole plant. It focuses on the load calculation of electrical equipment, line voltage drop verification, emergency power supply selection, etc. The application of sulfur hexafluoride and solidstate insulated high-voltage ring network cabinets in the design improves the reliability and safety of temporary power use; In the design, aluminum cables are used as high-voltage power supply lines, which greatly reduces the cost.