Abstract: The recent technology development of coal-fired generation unit drives the progress of corresponding auxiliary equipments and their design techniques. Take the example of the electrostatic precipitator (ESP) installed in a 1 350 MW double reheat ultra supercritical coal-fired unit in Anhui province with cross compound steam turbine arrangement featured by separated shafts with elevated and conventional layout. The schemes for ESP type selection are analyzed and different combinations are compared, i.e., two sets with four-chamber and five-field, three sets with three-chamber and five-field, four sets with two-chamber and five-field of ESPs. Especially regarding the four-chamber ESP with better economic performance, the problem of insufficient strength caused by thermal expansion is analyzed by a finite element analysis software package and then the pre-eccentricity of pivots is developed. The result shows that the thermal expansion has significant impacts on the strength of the steel frame of large size ESPs and the pre-eccentricity of pivots can effectively reduce the internal force and deformation.