According to the distribution characteristics of ship targets in infrared images, the approximate locations of ships are determined first through sea-sky line/coastline detection and the Regions of Interest (ROIs) of the ship targets are determined by utilizing the area characteristics of the targets. The sea-sky line/coastline is detected by using median filtering, Canny edge detection and Hough transform methods and the sea-sky line/coastline area is delineated. Then, the ROIs are determined according to the area characteristics of the ships. The algorithm is implemented by Vc programming. The results show that this method is simple and intuitive and can be used to determine the ROIs of ship targets near shore effectively.