To limit the wind-induced deflection amplitude of an overhead conductor, this study proposes a calculation model and an optimization model for overhead lines. According to the geometric deformation relationship and the principle of energy conservation, a multi-rigidbody model (MRBM) is proposed for the wind-induced deflection of the overhead lines. An aeroelastic model wind tunnel test was designed to verify the accuracy of the MRBM; the efficiency of the MRBM was verified through comparison with the finite element model (FEM). The optimization model is presented, and the structural parameters of the transmission lines in the actual project are optimized and analyzed. The results show that the accuracy of the MRBM can meet engineering requirements; the solution time is shorter than FEM, and the MRBM is easily called by the optimization algorithm. The structural parameter optimization effectively limits the deflection amplitude of the overhead conductor according to the engineering requirements.