Low illumination color images enhancement plays a significant role in our daily lives,and traditional algorithms for enhancing low illumination color images often cause varying degrees of image distortion.To improve the contrast of color images in low illumination without causing image distortion,a novel adaptive contrast enhancement algorithm of low illumination images is proposed in this article.A novel fractional Retinex image enhancement algorithm is constructed by combining fractional calculus,Retinex variational method,and the piecewise logarithmic transform saturation enhancement method.Experimental results show that this method can not only improve the contrast of color image,but also preserve the edge and texture details.Compared with existing low illumination image enhancement algorithms,it can highlight the detailed texture information of color image,and has a significant improvement in image chromaticity and brightness compared with existing state of the art enhanced algorithms.