<p>To address the degradation of electrical performance of very low frequency (VLF) Trideco antennas under multi-source loading, this study proposes an electrical-performance-oriented integrated structural-electromagnetic modeling and optimization method. Considering extreme loading conditions such as gravity and ice accretion, and based on the radiation principles of VLF Trideco antennas, the far-field radiation formula under multi-source loading is derived, and an integrated structural-electromagnetic model coupling the antenna structure and electromagnetic behavior is established. Taking the radiation resistance as the optimization objective, cable initial prestress as the design variable, and the tensile strength limit of the cable material as the constraint, an integrated structural-electromagnetic optimization model is developed oriented toward electrical performance. Using a Bayesian optimization algorithm and a practical Trideco antenna as a case study, the optimization results demonstrate significant improvements in antenna performance under adverse conditions. Compared with traditional designs that minimize sag, the proposed integrated structural-electromagnetic optimization increases the radiation resistance by 14.18% and reduces the maximum structural deformation by 42.52%, thus verifying the effectiveness of the proposed method.</p>