Abstract: Deep soft soil deposits are widely distributed in China’s coastal areas. Surcharge preloading, a widely adopted method for soft soil ground improvement, tends to induce significant lateral soil deformation, which poses a direct threat to the safety and stability of adjacent high-voltage electric towers. Based on a practical engineering project, this study systematically investigates the laws governing the deformation influence of surcharge preloading on adjacent high-voltage electric towers, and examines targeted deformation control measures as well as their protective effectiveness. Taking the Jingang Avenue Project in Jinwan District, Zhuhai City as the research case, a refined three-dimensional (3D) surcharge model is established via finite element simulation to analyze the deformation response of adjacent high-voltage electric towers under surcharge. According to the identified deformation characteristics, a semi-U-shaped protective system, consisting of a main pile row along the line direction and transverse retaining piles perpendicular to the line at both ends, is proposed, and its deformation control performance is verified. The research results show that: without protection, the inclination ratio of the transmission tower reaches 0.997%, close to the 1% limit specified in the Code for Operation of Overhead Transmission Lines, and the maximum bending moment of piles adjacent to the surcharge exceeds their normal section flexural bearing capacity, indicating a significant safety risk; after the protective system is applied, the tower inclination ratio drops to 0.44% (a reduction of 56%), the maximum bending moment of the adjacent piles decreases by more than 70%, and the horizontal displacement of the surrounding soil is reduced by 64%. The semi-U-shaped composite protective pile system constructed with multiple deep protective piles can effectively block the transmission of lateral soft soil deformation, significantly mitigate tower inclination and pile stress, and thus ensure the safe operation of high-voltage electric towers.