Abstract: Compared with the nearby undisturbed seawater the temperature difference in the ship wake is tiny and the ship wake presents obscure configuration. These induce the low contrast of the infrared ship wake image and the borders of the wake images are difficult to be extracted. According to the characters of ship wake and infrared wake image, a border detecting method by dynamic texture and mathematical morphology was proposed. Firstly, the infrared wake image sequence was pre-segmented by dynamic texture method, and then the edges in the wake area were extracted by Canny operator. The extracted edges were dilated, labeled and selected by the mathematical morphology and the true wake borders were extracted. The experimental results show that processing the wake images by the methods mentioned above can effectively extract the borders of the ship wake and get better results.