The multi?circuit line configuration can effectively solve the problems in line reconstruction and construction amidst the increasing shortage of transmission corridors. The conductor spatial arrangement and phase sequence determination for long?distance transmission lines pose great challenges in the design and maintenance of overhead transmission systems. This paper utilizes the ATP?EMTP simulation software to build a model of 500 kV four?circuit transmission line on the same tower, and simulates the induced voltage and current values with different line lengths, tower spacings, vertical and horizontal inter?circuit gaps, phase sequence arrangements, and tower nominal heights. Employing a BP neural network optimized by genetic algorithm, this paper achieve to predict the induced voltage and current values under unknown conductor spatial arrangements and phase sequences. Subsequently, according to the relevant electromagnetic environment control criteria, the multi?objective particle swarm optimization algorithm is used to optimize the conductor layout and phase sequence arrangement for overhead transmission lines. This process yields a four?circuit conductor arrangement meeting the electromagnetic environment requirements, thus providing a reference for the selection of substation grounding switches.