Abstract: Terahertz radar can obtain the detailed scattering feature of targets, which is of great significance for target detection, imaging and recognition. In this paper, the scattering center modeling of radar target in terahertz band is discussed. The inherent physical relationship among the scattering center model, the target echo and the target imaging result is analyzed. A new method of target scattering center modeling is proposed based on the full wave approach(FWA) and the signal filtering method, which can describe both the traditional coherent scattering center and the non-coherent scattering behavior of rough targets. The method provides an effective description for the scattering echo simulation of rough targets in terahertz band.