Topographic effect is one of the main obstacles in quantitative analysis of remote sensing. For the airborne hyperspectral remote sensing, both of the impact of terrain height and angle can’t be ignored, and this causes more severe topographic effects. By taking the CASI image and LiDAR data of Qinghai Province as experimental data, the impact of elevation factor was analyzed in this paper. Firstly, on the premise that each elevation point is a horizontal Lambert body, four different elevation values were taken as reference to calculate the corresponding atmospheric radiation correction parameters by performing MODTRAN, which contain path radiance,atmospheric transmittance between the object and the sensor, atmospheric hemisphere albedo, and total downward radiance. Then an atmospheric radiation correction method with elevation factor was designed and applied to the atmospheric correction of CASI image. Finally, the CASI hyperspectral image was also processed by using FLAASH, which could only take one elevation value as reference. A comparison of two results shows that the reflectance spectrum shapes of the same ground objects are roughly the same,but the reflectance values are different. Especially, the short-wavelength reflectance values of FLAASH results are negative, and it is undoubtedly wrong. The experiment shows that the impact of elevation factors can’t be neglected. Atmospheric correction by adding elevation factors can get better results. For achieving accurate topographic correction of airborne hyperspectral image, both elevation and topographic angle factors should be considered simultaneously.