Abstract: Due to the multiple hazards to the ecological environment, human health and power production, the emission of SO₃ from the flue gas of coal-fired power plant has attracted wide attention. The in-depth study and systematic summary on its emission control characteristics are the basis for formulating relevant policies and implementing emission control work in the next step. In this paper, the previous research results and current research progress were summarized from two aspects of SO₃ synergistic control technology and specific control technology, and the key problems to be solved and the research contents to be carried out are analyzed. Combined with the characteristics of coal-fired conditions, boiler type and ultra-low emission equipment of coal-fired power plants, the feasible technical routes to different SO₃ emission requirements were analyzed to provide a reference for the follow-up related technical research, engineering practice and policy-making.