Single infrared or visible light band imaging technology is insufficient to meet the requirements of color imaging in night and foggy days. To overcome this problem, a color video construction method for fixed area in night and foggy days is proposed, which combines the characteristics of infrared imaging and visible light imaging. The proposed method constructs the visible background image by using visible light sensor during daytime with high visibility, and extracts the infrared moving target by using infrared sensor in night and foggy days with low visibility. Then, according to the registration parameters of the visible background image and the original infrared image, the two images fuse in the same proportion, and the construction of color video is thus completed. The experimental results show that the proposed algorithm can accurately complete the construction of color video with infrared target. It fully reflects the color feature information of the moving target and its scene in night and foggy days, and enhances the recognition and perception of target and scene information by the human eye. For a video sequence with an image size of 720 pixel×576 pixel, the running speed of the algorithm can reach 40 frame/s and meet the the need for real-time construction of color video.