To deal with the hale phenomenon at the image edges, image hue、tone and brightness distortion problems in the classic dark channel theory algorithm, enhancement dark channel algorithm of fog image based on the total variation (TV) model is proposed.The rough transmission image based on the dark channel theory mathematical model is smoothed by the TV model. The image is segmented by the tolerance mechanism and distinguishes sky areas, so as to solve the halo phenomenon in the image highlight area. According to the dark channel theory mathematical model, it gets a defogging enhancement image from the inverse solution. Through the subjective observation and objective evaluation, the algorithm is better than the classic dark channel algorithm in the overall and details.