In order to achieve the atmospheric pollutants emission standards of thermal power plant, the common modification technical routes of the denitrification, desulfurization and dust removal system of 1 000 MW ultra-supercritical coal-fired units are studied. The actual operation of the flue gas environmental protection facilities such as denitrification, desulfurization and dust removal of 1 000 MW coal-fired units are obtained. The requirement that the coal-fired units in Guangdong province basically reach the gas turbine emission limit is issued by the development and reform commission of Guangdong province. According to the gap between the actual operation and the emission limit of the coal-fired units, the problems of ultra-low emission of the units are analyzed and discussed. From the viewpoint of the feasibility of the process, investment, duration, and the operation and maintenance costs, the modification schemes of 1000 MW unit environmental protection facilities are researched. The appropriate reform projects of the flue gas environmental protection facilities are determined, which can reduce the emission of atmospheric pollutants, i．e., NO_x, SO₂ and flue gas, below 50，35，10 mg/m³.