Abstract： The images restored by using the dark channel prior theory have haze edges. Therefore, a novel improved image clearness method based on dark channel prior was proposed to solve this insufficient. First, dark color image was obtained and decomposed by wavelet. Next, the smooth portion  from wavelet decomposition was used as the target image, in which global atmospheric optical A and the dark channel value were calculated, and then, the edge information of target image was extracted and dilated. After that, according to the expanded binary edge image, the dark channel value in edges and that in smooth were optimized, respectively. Finally, according to the transmission map calculated using the optimized dark channel values, the fogfree image was obtained by using the physical model. The experiment results show that this method can effectively restore the fogging images and greatly reduce the time complexity brought by the soft matting algorithm.