Abstract: With the implementation of the“Emission Standard of Air Pollutants for Thermal Power Plants”( GB 13223— 2011) ，the key regions have to execute the most strict emissions standards that the dust emission concentration is required to be lower 20 mg /m3 ． In order to meet the requirements，the existing electrostatic precipitators ( ESP) need to be reformed． The wet electrostatic precipitator ( WESP) can further reduce the particle，droplet and heavy metal concentrations． Through the improvement of the traditional wet electrostatic precipitator，we developed the deep purification system with flexible collection electrode to purify the flus gas after the flue gas desulfurization ( FGD) ． The technology as a demonstration project of China Guodian Corporation is for the first time used in large units of thermal power plant． The engineering project attracts the attention of environmental protection field． The commissioning results demonstrate that the WESP has high adaptability，dust and droplet removal effect，and unaffected by the coal smoke characteristics． It will have a good development prospect．