Abstract: The electric field intensity around transmission towers is a critical metric in line optimization design and safety assessment for live-line maintenance personnel. Currently, the construction of electric field calculation model, however, still relies on parameters extraction from technical drawings and human intervention, resulting in low efficiency and inadequate automation. To address this issue, an intelligent key points extraction model for towers is established based on high-precision point cloud data, and an automated construction method for electric field calculation models of transmission towers is proposed. Firstly, a local coordinate system is established for tower point cloud, followed by segmentation of tower body and tower head components. Secondly, for the tower body, coordinates of key points are directly calculated by handcrafted features, while for the tower head, the LACV-net key points extraction model is employed to locate key points. Finally, integrating conductors positions and points-surfaces topology of the transmission towers, the electric field calculation model is constructed. Case studies demonstrate that, compared with classical algorithm, the proposed method reduces key points extraction deviation of the tower head by 75% and decreases extraction time by 73.6%. Furthermore, compared with drawing-based modeling, the electric field intensity calculation deviation is 5.7%, validating the effectiveness of the proposed method.