Abstract: Aiming at the problems of dark environment and blurred target in coal mine, this paper presents a method of image sharpening in coal mine based on multi-transmittance fusion. First of all, combined with the image de-fogging method, the image HSV channel is processed with minimum filtering, and the maximum value is taken and converted to RGB value as atmospheric light. Then, the multi-transmittance fusion method is proposed. By obtaining the multi-scale dark channel image, the transmittance corresponding to the multi-scale dark channel is obtained, and the fusion method is designed to fuse multiple transmittance. Finally, using the atmospheric light and transmittance obtained, the clear image is obtained according to the atmospheric scattering model to realize the clear image in the coal mine. Experiments show that the proposed method can effectively improve the image quality, subjectively improve the details of the image, enhance the overall brightness of the image, and objectively improve the information entropy, average gradient, fuzzy coefficient and structural similarity.