Abstract: To study the power frequency electric field under the real environment precisely, based on the finite difference method, this paper utilizes a method that is approximate to terrain ladder triangulation and improves the finite difference method, thus realizing the 3D simulation of the distribution of the power frequency electric field under the condition of real terrains. The calculation model considering the real terrains greatly improves the accuracy of the power frequency electric field.The results from the proposed modeling can provide reference for transmission line design and electromagnetic environment analysis when erecting high voltage transmission line in complex terrains.