Abstract: The mechanism for energy saving and emissions reducing of High Frequency Power Supply for ESP was analyzed. Its research and application at home and abroad were introduced, and its advantages compared with traditional power supply were pointed out. As one case, the dust-collector retrofit of Unit 8 of Shanghai Waigaoqiao Power Plant was studies for investigating the energy saving and emissions reducing effect. During daily operation after the retrofit of applying High Frequency Power Supply for ESP, the dust emissions decreased by 59.5%, from 42 mg/m³ to 17 mg/m³, and the energy consumption decreased by 71.7%. According to this application case and the successful experience in coal-fired units of other power plants, the potential of energy saving and emissions reducing in the power industry of China was analyzed. On the base of related statistical data from the power industry in 2009, if all the ESP adopted the High Frequency Power Supply, the electricity consumption of the ESP would decrease by 3.15 billion kW·h, equal to saving 1.077 million tons equivalent coal, and the total dust, SO₂, NO_x, CO₂ emissions would decrease by 1.2-2.1 million tons, 10.7 thousand tons, 6.462-9.693 thousand tons, 3.10 million tons ,respectively.