Substation lead-down structure system is generally bundled conductor, and has the characteristics of small span, large height difference, short length and upper and lower connection. Substation lead-down accidents caused by strong wind often occurs. In order to study the nonlinear wind-induced response characteristics of the lead-down line under wind load, the Auto-Regressive model method is used to simulate the fluctuating wind load, and the modal analysis and the nonlinear time history analysis of the wind-induced response of the flexible lead-down system are carried out. The effects of aerodynamic damping, wind direction, Span-to-height ratio and number of spacers on wind-induced vibration response are studied. The analysis results show that the response of lead-down system has obvious non-Gaussian characteristics; Compared with the conventional horizontal long-span transmission lines, the natural frequency of lead-down line is higher, the influence of aerodynamic damping is smaller, and the response wind-induced vibration coefficient is larger. The wind load in plane will lead to larger reaction response, and the wind load out of plane will lead to larger displacement response. The increase of Span-to-height ratio will lead to the increase of reaction response and the decrease of displacement response of the structure. The mid-span displacement response of the structure increases with the decrease of the number of spacers, while the reaction response of the end point is the smallest when the spacer number is 5. The wind vibration coefficient of the internal force response and the displacement response of the down lead are not the same, which are obviously larger than the results of the general long-span transmission line.