An improved approach on single image dehazing is proposed in order to obtain clearer restored images. Firstly, the source images are converted into YUV color space, and then, pixels are divided into different areas, only those pixels belong to the same areas in Y channel are used to calculate Dark Channel, and the air light value are also calculated in Y Channel. Finally, the distortion of bright area is adjusted through modifying the formula by which the restored image is calculated. Compared with those algorithms based on dark channel prior with guided filter in RGB color space, this algorithm is more effective.