As the main equipment of flue gas dedusting in coal fired boiler, electrostatic precipitator (ESP) can meet the requirements of emission standard for air pollutants from coal-fired power plants through improving the efficiency of ESP and combining with desulfurization system while not installing wet ESP (WESP). This paper introduces the modifications of ESP cathode structure to improve the efficiency of dust collection by reducing the secondary dust loss at cathode. The application of cathode dust collection provides a reference for the improvement of ESP dust collection efficiency.