Remote sensing image radiation correction is a key technique for quantitative remote sensing data processing is essential, especially in the surface undulating mountains, surface radiation affected by topography, the radiation correction of remote sensing inversion error can reduce the surface information, so as to maximize the accuracy of remote sensing investigation of mountain area. In this paper, the ETM image in mountain area of Western Beijing as an example, application of cosine correction model and Sandmeier correction model of image are topographic radiation correction, and then proposed an improved Sandmeier correction model, and carries on the precision analysis from the visual effect and quantitative parameters. Experiments show that, the improved Sandmeier correction model eliminates the influence of topography, greatly improving the accuracy of remote sensing image Topographic Radiation correction.