Aiming at the problems of uneven illumination of underwater image cause d by supplementary illumination of deep sea and night waters,image noise,low contra st and color deviation caused by suspended particles in water,an underwater image enhancemen t method with nonuniform illumination is proposed.Firstly,the noise of underwater ima ge is removed by Gaussian filter.Secondly,the maximum inter class variance (OTSU) method is used to segment the light and dark region mask of the image, divide the brightness map into light and dark regions, and homomorphic filtering is performed on the dark regions to correct the shadows caused by uneven illumination. Then,the new brightness map is obtained by fusing the light and dark areas with weighted aver age method, and the color image is synthesized again.Finally,the underwater image is proce ssed with contrast limited adaptive histogram equalization (CLAHE),and gray world to enhan ce contrast and color distortion correction,get enhanced underwater image.The exp erimental consequences express that the proposed method can valid ameliorate the uneven illumination problem,remove the underwater image noise and enhance the image co ntrast, which is conducive to the subsequent target detection,tracking and other tasks.