The conversion of sensor the top of the atmosphere signals （TOAS）, to reflectivity representing land surface target characters is an important sector in remote sensing information quantification. Assuming atmosphere disturbance being excluded, because of adjacency effect among pixels, the DN value of a target pixel contain the scatter contributions of background pixels. The magnitude of the contribution is directly proportional to the background pixel reflectivity and is correlative with the distance to target pixel. According to the results of carder（1995） and Christopher（1998）, the influence of adjacency effect exceeds that of mixed pixels when the spatial resolution is greater than 250 m. Along with the increase of satellite spatial resolution and remote sensing information quantification degree, adjacency effect and its correction method are paid attention to. Recently, supported by NSFC, we have carried out a research on them. Based on radiation transfer model, the adjacency effect in a scene of Landsat5 TM data of Beijing is analyzed and corrected to comprehend the general characters of adjacency effect