In this paper, time-domain physical optics (TDPO) method is extended to its iterative version (TDIPO) to consider the coupling efiects between two regions, and the latter is employed to investigate electromagnetic scattering from three dimensional target half-buried by a two dimensional rough surface. By using iterative scheme, more accurate transient response re∞ected from combinative target with multi-scattering efiects would be obtained than that by using TDPO alone. The TDIPO could also be enhanced by time-domain equivalent edge current (TDEEC) to further determine the far-fleld characteristics of the combinative target with rough surface. An accurate composite geometry model technique which combines 2D perfectly electrically conducting (PEC) rough surface and half-buried 3D PEC target is introduced and employed to assist the meshing work. The validity of the presented method is verifled by comparing the scattering results for dihedral targets with those obtained through TDPO and flnite difierence in time domain (FDTD), as well as multi-level fast multiple algorithm (MLFMA). Then simulations of EM scattering from the target embedded in rough surface for difierent incidence directions are carried out to test the availability of TDIPO/EEC. Discussions on the efiects of incidence direction and the presence of the target on the backscattering in far- zone are also given.