Based on a quantitative study of the incident angle effect of a wide-swath synthetic aperture radar（ SAR） image

this paper proposes a class-based correction method for such an effect. The method achieves sampling by using watershed segmentation and regional labeling technology as well as a class-based radiation correction of land-cover backscatter values based on the cosine Lambert’s law estimated through linear regression. Experimental results of the Envisat Advanced SAR（ C-band horizontal-transmitting

horizontal-receiving polarization） data show that an incident angle effect is exerted on radar backscatter; the higher the moisture content of the land-cover type is

the more obvious the incident angle effect is. The correction of incident angle effect with this proposed algorithm is better than order cosine correction.