Abstract: In view of problem that existing image fuzzy enhancement algorithm of underground coal mine cannot deal with the situation when the image is in fog and the processed images are obscure, the paper proposed an enhancement technique of underground image based on dark channel prior. The technique uses linear fuzzification function to achieve the purpose of image enhancement, and adopts dark channel prior theory to enhance image contrast, meanwhile realizes defogging and dedusting. The experimental results show that the proposed technique can improve visibility of underground image and significantly enhance image contrast.