As the absorption and scattering of light in underwater propagation,problems such as fuzzy,low contrast,color deviation and uneven illumination appear in underwater images taken.In view of the above problems,an improved underwater enhancement algorithm based on Gamma correction and multi-scale fusion is proposed.Firstly,Red and Blue channels are compensated based on Green channel,and the correction image is obtained by Gray World algorithm after histogram stretching of RGB three channels.Then,the color corrected image is corrected for uneven illumination by using the improved Gamma function to obtain the uneven illumination corrected image,and the illumination uniformity image is normalized.Then,the contrast of the image after uneven illumination correction is improved by contrast limited adaptive histogram equalization (CLAHE)algorithm to obtain the contrast improved image.Finally,the multi-scale fusion algorithm is used to fuse the above three images to obtain the enhanced image.Experimental results show that the proposed algorithm has good processing effects on images in different underwater environments,and the image quality evaluation index is significantly improved.