Abstract: The steady-state response Problems of tall building structures on semi-infinite elastic subgrade, subjected to multi-dimensional deterministic dynamic loads, were converted into the boundary problems of ordinary differential equations by means of analyzing and predicting the time-varying property of the steady-state responses in the paper. A reasonable conclusion was drawn from the rend of an example of a tube-in-tube tall building structure. It is found that the response of the structure experiences enormous increment when the frequency of the excitation load is very dose to the natural frequency of the structure.