Due to the absorption and scattering of light in the water environment ,the collected underwater image has the defects of color distortion,blurred de tails,uneven illumination and poor contrast.Therefore,an underwater image enh ancement method based on brightness correction and multi-space transformation i s proposed to resolve this defect.Firstly,color balance algorithm is used to co rrect the color of degraded images.Secondly,the color corrected image is conve rted from red-green-blue (RGB) space to hue-saturation-value (HSV) space,the Vchannel is processed by the constructed two-dimensional function,and then transferred back to RGB space.Finally,the w eighted fusion of color balance image and brightness correction image are carrie d out,and the fusion image is converted from RGB space to LAB space.The Lchan nel is processed by the contrast-limited adaptive histogram equalization algori t hm,and then transferred back to RGB space to obtain the final enhanced image.I n order to verify the effectiveness of the algorithm in this paper,subjective v isual effects and three objective indicators are used for verification.The resu lts show that this algorithm can effectively correct image brightness and improv e image clarity.