Abstract: An approximate 3DOF model for transmission tower-line system has been established,which is combined with softening nonlinear stiffness of tower by static FEM analysis and dynamic characteristics of conductor after distorted under mean wind load. Utilizing the method of statistical linearization, the analytical solution of stochastic response of tower-line coupling system under strong wind is derived. Comparing with numerical simulation, results show that the analytical solution by the herein developed procedure can be not only enough precise for engineering but also an auxiliary tool in judgment of the critical wind speed.