Abstract: To further increase the temperature and efficiency of SCR denitration, innovative idea of arranging preposition economizer in bypass flue was put forward. Meanwhile, a clean and efficient waste heat utilization system, which combined in-depth waste heat utilization and low-low temperature ESP, was proposed. Based on the actual data of a typical 1000 MW coal-fired ultra-supercritical unit, thermodynamic, pollutant emission reduction and economic performance of the proposed system were comprehensively researched. The results indicate that, for 1000 MW coal-fired ultra-supercritical units, the proposed system can reduce the standard coal consumption by 3.08 g/（k W?h）, while increase the denitration temperature and efficiency by 16-18℃ and 4.0%-8.5% respectively. The proposed system can also increase the efficiency of ESP remarkably, and reduce water consumption of desulfuration by 1082.5 t/d. Regarding economic performance, the additional investment of the proposed system is approximately 62.756 MCHY. The static payback period is 6.8 years and the net income is 3.077 MCNY per year. Overall, the proposed system presents great energy-saving effect, excellent environmental protection performance and considerable economic benefit. The research results of this paper provide innovative integration idea and technique option for achieving the great-leap-forward development and the goal of clean and efficient of coal-fired