In the process of UHV substations design, determine the distribution of electric field near the space electric field especially substation equipment is very important. For substation equipment near the complexity of the electric field distribution, the three-dimensional boundary element method is proposed for Jingmen 1000 kV substation equipment to simulate the electric field research, the extremum of three-dimensional synthetic electric field was deduced formula, and through the ANSYS simulation software to establish the corresponding simulation model, for validation of this method, the theoretical calculation results and simulation results are basically identical, prove the correctness and validity of the algorithm.