The dehazing algorithm for image processing is widely used to improve image quality, which aims to reduce the impact of hazy weather. The typical dehazing algorithm using dark channel prior (DCP) can carry out image dehazing efficiently. However, the processed image only by using DCP will lead to the low lightness and the weak colour of the image, which cannot meet the visual characteristics of the human eye in some extent. To solve this problem, this paper proposes an image fusion dehazing algorithm based on DCP and retinex. First, the original image is processed by the DCP dehazing algorithm to get the dehazed image. Then, the dehazed image is processed by using the retinex algorithm to get the enhanced image. Finally, the dehazed image and the enhanced image are fused using a linear fusion method, which is expected to improve the lightness and colour of the image after dehazing. Experimental results show that the algorithm proposed in this paper not only achieves good results for image dehazing, but also enhances its lightness and colour.