Residents’ living condition and project environment evaluation are affected greatly by noise and electromagnetic pollution caused by substation corna discharge, which must be suppressed. According to the actual layout and structural drawings of related equipment and fittings, taking measured results of substation corna discharge as reference, and considering the effects of three phases and surrounding conductors, an electric field finite element simulation model for 220 kV substations’ typical discharge positions is built by the finite element method ( FEM ) software ANSYS. The maximum surface electric field magnitudes of the fittings are calculated, the surface electric field distribution conditions are obtained, the structure of those corona fittings is optimized based on the calculation results and corona noise suppression measures are put forward. The results show that after structure optimization, the distortion of electric field distribution of the fittings is declined greatly, and the maximum surface electric field magnitudes are reduced to less than 3 000 V/mm. This research provides important reference for prevention of corona and reduction of substation noise, and supplies basis for construction of green grid and substation.