Abstract: The structure-soil dynamic interaction is mainly confined in frequency domain because of the difficulty of determination of dynamic effects of infinite medium on structural response, which makes most of the dynamic interaction analysis methods invalidated for nonlinear problems. Damping Extraction Method is an effective simple procedure, which can simulate the dynamic properties of non-homogeneous infinite medium by applying artificial damping and then shifting the frequency along frequency axis. Based on DSEM, it is convenient to get dynamic interaction force in time domain acting on interface between unbounded rock and structure. In this paper, an adaptive damping-extraction procedure is proposed for the dynamic interaction analysis of structure-unbounded rock system. The corresponding FE numerical implementation of the procedure in time domain is given by precise step-by-step time integration scheme, which can be conveniently combined to the existent FE program for dynamic soil-structure interaction in time domain. Some key factors in implementation are discussed. Several applications are presented and demonstrate satisfactory accuracy and excellent application prospect.