Aiming at degeneration of UAV’s farmland aerial images in rainy or foggy weather, this article proposed an integrated method based on dark channel prior(DCP) and optimized contrast enhancement(OCE). Firstly, this method identified the existence of sky from the original image, and then segmented and feathered the original images in Gauss method with Canny edge detection algorithm. Secondly, the nonsky regions, where luminance value was low, were filled with binarized dilation and morphological erosion removed. Finally, both nonsky and sky regions within a frame were processed by dark channel and optimized contrast enhancement algorithm respectively. In this research, the effect of the proposed algorithm was evaluated by noreference quantitative assessment using 100 aerial photographing images. The experimental results showed that the possibility of Halo effect, compared to DCP, was reduced by 95% while its comprehensive evaluation average index was raised by 26%. Consequently, without obvious transition region and color cast, the proposed method filtered the fog of the aerial images well and the color reproduction was high. Meanwhile, the average processing efficiency in the proposed algorithm was up to 32% (33 frame per second) higher than classical DCP. Hence, the method could met the realtime requirements.