The harsh weather conditions cause some problems such as low contrast of the aerial image and missing details.In this paper,we propose an algorithm of histogram specification based on the adaptive function to enhance aerial image.In this method,firstly the histogram is divided into four sub-la yers equally,and then according to the probability density distribution,we will re-map gray value range of sub-layer s to complete the expansion of the dynamic range,thereby increasing the contrast of the image.In order to enhance the image details better,we maximize entropy under the constraint of constant brightness in each sub-layer. Experimental results show that the image contrast using the proposed algorithm has been increased,while the im age detail and texture information have also been enhanced.