Abstract: To deal with the image hue and brightness distortion problems in the classic dark channel theory algorithm, enhancement dark channel algorithm of color fog image based on the anisotropic Gaussian filtering is proposed. Firstly, the image was segmented by the tolerance mechanism and distinguished between bright areas and dark channel areas according to the threshold. Then, the edges of the transmission image were preserved and the others were smoothed by the anisotropic Gaussian filtering. At last, the obtained image was modified to get the accurate transmission image by the tolerance mechanism in order to get a defogging image. Through the subjective observation and objective evaluation, the algorithm is better than the classic dark channel algorithm in the overall and details.