Unlike traditional building structures, transmission tower foundations endure significant vertical and horizontal loads, with particularly high uplift resistance requirements in complex terrains. Moreover, challenges such as difficult material transport and low construction efficiency arise in these regions. This study, based on practical projects, proposes a novel high uplift resistance prestressed concrete prefabricated foundation (HURPCPF) tailored for transmission line systems in complex terrains. A refined finite element model is developed using ABAQUS to analyze its performance under uplift, compressive, and horizontal loads. Comparative studies with cast-in-situ concrete foundations evaluate the HURPCPF’s bearing capacity, while parametric analysis explores the impacts of foundation depth and dimensions. The results show that the proposed HURPCPF exhibits a linear load–displacement relationship, with uniform deformation and good integrity under compressive and uplift conditions. During overturning, the tilt angle is less than 1/500, meeting safety standards. The design of prestressed steel strands and internal reinforcement effectively distributes tensile stress, with a maximum stress of 290 MPa, well below the yield stress of 400 MPa. Compared to cast-in-situ concrete foundations, the displacement at the top of the HURPCPF’s column differs by less than 7%, indicating comparable bearing performance. As foundation depth and size increase, vertical displacement of the HURPCPF decreases, enhancing its uplift resistance.