The grounding method for follow-bridge cables critically impacts operational safety and stability. This study models a cable system in Zhejiang, analyzing unified grounding versus three-phase separate grounding across three segments: upper bridge, sea-crossing, and lower bridge sections. Results demonstrate that a hybrid approach—applying separate grounding at both bridge ends and unified grounding in the sea-crossing segment—significantly reduces sheath current magnitude and lowers unbalance in the sea-crossing section, thereby improving electrical performance. The research provides key theoretical and practical guidance for grounding method selection, emphasizing that rational grounding enhances system stability. Further empirical studies can offer precise data support for engineering optimization, ensuring safer and more efficient power transmission.