The seaskyline extraction is one of the most important parts of ship detection and tracking, good extraction results can determine the target area as soon as possible, it can also be a substantial reduction in the complexity of the detection and tracking. The traditional onedimension OTSU algorithm is susceptible to noise interference, which could affect the accuracy of the results, and cause erroneous detection. To solve the noise problem based on the complex seasky background, this paper chooses the morphological filter to reduce the noise first, then using twodimension OTSU to add the spatial information of the image to threshold criteria, using a twodimension matrix to determine the final result of the threshold. After amount of experiments on the multiple visible and infrared images, it proves that this paper’ method can reduce the noise effectively, and also extract the seaskyline perfectly.