In order to improve the precision of ship attitude, a new method for attitude measurement was proposed based on sea-sky-line. Making use of the characteristic of ocean environment, based on horizontal attitude of sea-base platform, image processing and target extraction method were analyzed, model for measuring attitude was built. Then, ship attitude can be detected from the sea-sky-line area. Simulation and the experimental result analysis were analyzed. The simulation result showed that attitude of ships can be calculated by using this method with high precision.