Considering the images captured under hazy weather conditions are blurred, a new dehazing algorithm based on overlapped sub-block homomorphic filtering in HSV color space is proposed. Firstly, the hazy image is transformed from RGB to HSV color space. Secondly, the luminance component V is dealt with the overlapped sub-block homomorphic filtering. Finally, the processed image is converted from HSV to RGB color space once again. Then the dehazing images will be obtained. According to the established algorithm model, the dehazing images could be evaluated by six objective evaluation parameters including average value, standard deviation, entropy, average gradient, edge intensity and contrast. The experimental results show that this algorithm has good dehazing effect. It can not only improve degradation of the image, but also amplify the image details and enhance the contrast of the image effectively.