This paper presents an objective evaluation method f or image enhancement combining blind image quality index (BIQI) with just noticeable difference (JND).The metho d divides the test image into a reflection image and an illumination image base d on Retinex theory,and the reflection image and the illumination image wer e evaluated respectively.The sum of the scores is regarded as the score of the objective evaluation of image enha ncement.A series of experiments on the variable control of the original image distortion and background brightness show that the reflected image is affected only by the type and degree of distortion,while the illumination image repre sents the original image of the environmental light information and has the effe ct of luminance threshold.After image enhancement,the algorithm in this paper can get the highest score of 0.609〖KG － 1/6〗3and the result is consistent with subjective evaluation result.As peak signal-to-noise ratio (PSNR) and structural similarity (SSIM) scores are both compa red with those of the original image,they can not reflect the effect of imag e enhancement.The experimental results s how that the algorithm can objectively evaluate the image enhancement and the ef fect is good.