The images of remote infrared targets acquired by a phototheodolite in the background of sea and sky have the disadvantages of low contrast, nonuniform gray level and a large number of noises etc. This may affect the interpretation of the target in the image severely. For this reason, an infrared image enhancement method based on bit-plane slicing and adaptive rainbow pseudo-dolor transform is proposed. The experimental result shows that the pseudo-dolor image enhanced by this method is more colorful and saturated. The details and edges of the target are clearer. Particularly, different color gradations can be identified from the edges of the target. So, it is more fit for human's visual habit.