Abstract: The intense electromagnetic coupling of each conductor of the quadruple-circuit transmission line on the same tower leads to severe three-phase current imbalance. To address this issue, using the simulation software of electromagnetic transient ＆ power electronics（EMTPE） first establishes an electromagnetic transient model based on actual transmission line parameters. The model’s effectiveness is verified by comparing simulation results with the practical measurements by the model. Then the primary factors of the three-phase current imbalance in the transmission lines are analyzed through the model. The analysis indicates that improper arrangement of conductor phase sequence and spatial distribution are the main causes of the three-phase current imbalance in a specific quadruple-circuit transmission line on the same tower in Ningxia.A solution involving the adjustment of the phase sequence arrangement of one circuit to its opposite is proposed. Finally, in the context of engineering planning, the optimal phase sequence combination for each conductor in the quadruple-circuit transmission lines is presented, providing guidance and suggestions for future project construction.