Taken the 110 kV high-voltage transmission and distribution equipment and oil and gas processing facilities platform of an offshore CEPC platform as an example, the CST Studio Suite electromagnetic simulation software is used to make up the 3D modeling analysis. Through the numerical simulation method, the probes are set around the high-voltage cable, and the electromagnetic fields of different positions in the space around the cable are comparatively analyzed, which is compared with the existing standards. It is known that the electromagnetic field around 110 kV high-voltage cable is strong, which is of certain influence on the connected peripheral deck and platform pillar. However, they all meet the requirements of the existing standards for the public exposure control limits. In order to reduce the impact of the electromagnetic environment of the high-voltage cable on the personnel and equipment and facilities, the protective measures are taken by increasing the electromagnetic shielding, and the cable bridge frame and its thickness, and the cable spacing and layout are analyzed in detail. It is found that after the addition of the cable bridge frame and application of the stacked tripartite square configuration layout of the cable, the electromagnetic field strength around the 110 kV high-voltage cable is significantly reduced. The protective measures of high-voltage electromagnetic shielding proposed can provide important reference for the subsequent engineering projects.