Since there is lack of methodology to assess the performance of defogging method and the existing assessment methods have some limitations, a new objective quality assessment method for defogged images is proposed. For the halo artifacts, an edge-weighted structural similarity index is adopted to assign different weights to contour correlation and local texture correlation of the fog image and defogged image, which can represent the structural similarity. From the perspective of human visual perception, the normalized gray difference of defogged image is defined to describe the luminance of the image. Then, the fog image and defogged image are changed from RGB space to HSV space. Information entropy and histogram similarity of S component are used to assess the color performance of defogged image. Finally, with these three factors, a comprehensive image quality assessment model is established, which is used to make the objective evaluation and comparison. Experimental results demonstrate that the proposed method can achieve a consistent result with our subjective perception as well as obtain a good effectiveness and reliability.