Abstract: Domestic energy characteristic determines that the coal-fired power will remain the main power supply in China for a long time. The development of 700℃ ultra-supercritical units is one of the future development directions of coal-fired power generation technology with high efficiency and low-carbon emission.Moreover, the improvement of coal-fired unit parameters cannot be achieved without material innovation. In this paper, the potential materials of main pipelines of 700℃ ultra-supercritical unit are analyzed, GH 984G, Nimonic 263, Haynes 282 and Inconel 740H are proposed as the candidate materials for the main steam pipe and the high-temperature reheat steam pipe. At the same time, in order to reduce the construction cost of the unit and improve the comprehensive economy of the unit, the layout of the main plant, main steam and high temperature reheat steam pipe specifications are optimized, and suggestions on four pipe specifications and the layout of the main plant are put forward.