Several kinds of factors affecting the radiometric calibration of a large area array color CCD aerial mapping camera were presented through analyzing the process of camera imaging. Then,a model for radiometric calibration was established. The experiments of radiometric calibration were performed by using integrating sphere and in the dark field, respectively, and outputs of radiometric response of the camera were measured and analyzed through combination of changing the input radiance, exposure time, CCD gain and other factors. The experimental results show that the characteristics of radiometric response for R, G and B color channels are different when the input radiance is changed, but it varies linearly in the working spectral range. When the least square method is used to fit the calibration data of radiation, the goodness of fit for first-order polynomial shows that the R2 is above 0.999. Furthermore,when input radiometric luminance is constant,the output of the camera varies linearly with the exposure time or CCD gain, which lays the theoretical basis for the deduction of radiation response characteristic curves under the other work conditions. The data from radiometric calibration is applied to the exposure parameters, and experimental results indicate that the lightness of image is appropriate and its average gray value satisfies the requirement for exposure．