In the process of spaceborne camera imaging, the brightness of the scene changes with atomosphere and ground target. In order to obtain ideal images, an automatic exposure method based on land- atmosphere radiative transfer model for spaceborne camera is proposed. The irradiance model is established at the pupil of spaceborne camera according to the land-atmosphere radiation transmission characteristics. After analyzing the influence of atmospheric aerosol in remote sensing image, improving the irradiance model, and on this basis an automatic exposure is proposed. Through calculating the total irradiance and the ratio of ground target irradiance in the total irradiance, and adjusting the automatic exposure parameter of spaceborne camera to improve ground targets information as much as possible. Then the adaptive Laplace filter parameters are determined according to the atmospheric aerosol optical thickness, in order to enhance the details of the remote sensing images. The experimental results shows that the quality of the remote sensing images are improved greatly, on account of promoting information and contrast of remote sensing images with the proposed method.