Abstract: A typical 220 kV transmission tower with high-low legs in mountainous slope areas of mining areas was taken as the object, and factors such as tower leg difference (0, 1, 2, 3 m), plate thickness (200, 400, 600 mm) and surface deformation direction (0°, 45°, 90°, 135°) were considered to study the surface deformation resistance of the split-type protective plate under the action of horizontal tension, horizontal compression, positive and negative curvature of the surface. The results indicated that the split-type protective plate could effectively reduce the axial force and relative displacement of the foundation of the transmission tower with high-low legs, and its protective effect was closely related to the type of surface deformation, direction of surface deformation, and tower leg level difference. The protective effect of the split-type protective plate increased with the increase of plate thickness, but when the plate thickness increased to a certain extent, its comprehensive protective effect no longer significantly increased with the increase of thickness. 400 mm was the optimal thickness for the split-type protective plate to balance the protective effect and economy. When the length direction of the split-type large plate was consistent with the direction of horizontal or curvature deformation on the surface, the protective effect of the large plate could be fully utilized, but the effect was relatively poor under surface deformation along other directions.