This study investigates the sensitivity to soil surface characteristics of the new SAR: TerraSAR-X. Investigations on the relationship between SAR in X-band and surface soil parameters (soil moisture and surface roughness) are rare. The few papers found in the literature were based on scatterometer measurements (Ulaby et al., 1986), airborne SAR observations (Hajnsek et al., 2003; Baghdadi et al., 2007), and on modelled backscattering coefficient (Autret et al., 1989). The objective of this paper: realize a preliminary diagnostic on the potential of spatial SAR in X-band for the characterization of soil surface.