Abstract: The seismic responses of connecting tall structures with multi-towers under multi-support excitations of bilateral horizontal and vertical seismic actions are numerically simulated by time-history analysis, and a substructure method is carried out. The method uses the technique of matrix reduction to reduce the system matrices to a smaller set of degrees of freedom, and it can result in a significant savings in computer time in the same accuracy. The partial coherence effect and wave passage effect are considered in multi-support excitations. Through the analysis on the seismic responses of a connecting tall structure, the results show that the axial forces of the corridor bars are increased when considering the traveling-wave and the partial coherence in a horizontal orthogonal seismic action, and the wave passage effects are especially prominent, but the axial forces of the corridor bars are decreased when considering the vertical multi-support excitations.