Aiming at problems of color distortion, low contrast and atomization phenomenon in underwater images, a underwater image sharpening based on fusion of double transmission imaging model and Retinex is proposed. Firstly, the restoration algorithm based on improved double transmission underwater imaging model is used to solve the image atomization and brightness imbalance; secondly, the guidedfilter is introduced into the multi-scale Retinex enhancement algorithm with color recovery to solve the image color deviation; in addition, the automatic color enhancement algorithm is used to effectively improve the contrast; finally, each input images is fused with the corresponding weight map that obtained by combining contrast, significance and saturation to obtain a clear underwater image. Experimental results show that compared with existing novel algorithms, the proposed method can effectively combine the advantages of multiple single algorithms with the largest scale. The average value of underwater image quality evaluation index UCIQE is 6.03% higher than the comparison algorithms and the SURF feature matching points are significantly improved. It can effectively solve the problems of color, sharpness and contrast while preserving the details of the image, which is more in line with the visual effect of human eye.