Due to the absorption and scattering of light in the water environment,the collected underwater image has the defects of color distortion,blurred details,uneven illumination and poor contrast.Therefore,an underwater image enhancement method based on brightness correction and multi-space transformation is proposed to resolve this defect.Firstly,color balance algorithm is used to correct the color of degraded images.Secondly,the color corrected image is converted from red-green-blue (RGB) space to hue-saturation-value (HSV) space,the V channel is processed by the constructed two-dimensional function,and then transferred back to RGB space.Finally,the weighted fusion of color balance image and brightness correction image are carried out,and the fusion image is converted from RGB space to LAB space.The L channel is processed by the contrast-limited adaptive histogram equalization algorithm,and then transferred back to RGB space to obtain the final enhanced image.In order to verify the effectiveness of the algorithm in this paper,subjective visual effects and three objective indicators are used for verification.The results show that this algorithm can effectively correct image brightness and improve image clarity.