Abstract: The responses of a transmission tower-line system under multi-component multi-support excitations of SMART-1 seismic array are investigated. A three-dimensional finite element model of a transmission tower-line coupled system considering the geometric nonlinearity of a transmission line is established based on a practical engineering project. The multi-component multi-support seismic time history of SMART-1 seismic array is selected, and the responses of a transmission tower-line system with different unfold type angles under multi-component uniform and multi-component multi-support excitations are studied, respectively. The results show that the responses of a transmission tower-line system under multi-component multi-support excitations are larger than those under multi-component uniform excitations, but the increasing degrees vary with the change of angles, especially the vertical displacement of a transmission line is strongly amplified. The response of a transmission line is studied with different angles according to real multi-component multi-support seismic waves, and the multi-component multi-support earthquakes have different influences on a transmission line with different angles. The analysis results obtained could provide a reference for the aseismic design of transmission lines.