Substation lead-down structure system typically consists of bundled conductors and exhibits characteristics such as a small span, significant height difference, short length, and upper and lower connections. Substation lead-down accidents caused by strong winds are frequent occurrences. To study the nonlinear wind-induced response characteristics of the lead-down line under wind loads, the Auto-Regressive model method is used to simulate fluctuating wind loads. Modal analysis and time history analysis are carried out to examine the wind-induced responses of the flexible lead-down system. The effects of aerodynamic damping, wind direction, span-to-height ratio and the number of spacers on wind-induced vibration responses are studied. The analysis shows that the lead-down system’s response exhibits distinct non-Gaussian characteristics. Compared with conventional horizontal long-span transmission lines, the lead-down line exhibits a higher natural frequency and reduced sensitivity to aerodynamic damping. Wind loads in the plane result in larger reaction responses, while out-of-plane wind loads lead to greater displacement responses. An increased span-to-height ratio corresponds to heightened reaction responses and diminished displacement responses of the structure. The mid-span displacement response of the structure increases as the number of spacers decreases, with the smallest reaction response occurring when there are five spacers. Additionally, the wind vibration coefficient for internal force response and displacement response of the down lead varies. As the span increases, the wind vibration coefficient shows a decreasing trend.