A common problem encountered in biomass estimation from radar image is the terrain effects appeared in radar images. Topography changes the local radar incidence angle

determines the surface area to be illuminated by a image pixel. In addition

the underlying terrain influences the spatial structure of vegetation layer.It is a complex task to correct or reduce this unwanted fluctuation in radar backscattering due to topography. In general

both high-quality digital elevation model （DEM）and the dependence of backscattering of various land covers on topography are required.The radar backscatter model introduced in this paper simulates radar backscattering from vegetations on various slopes. The backscattering-slope relationships derived from simulation

and a DEM forms the basic for a model-based radar terrain effect correction method. If the multi-band or multi-polarization radar data exist

model simulation can help to infer the topographic information from one channel of radar image

and then use it to correct other channels.