This paper proposes detection and tracking method of moving ships through navigational image sequence. We proposed a detection method of moving ships through navigational image sequence taken by cameras installed at ship's bridge. Since the image is influenced by roll and pitch, the general image processing technique, such as Background Difference method cannot be used. So we proposed a novel technique to eliminate the influence of roll, pitch and sea waves in the images. Moreover, we propose a tracking technique of moving ships through navigational image sequence. We verified the advantageous of our proposed technique by several experiments at Tokyo Bay. The small ships that could not be detected by AIS and radar would be able to detected and tracked. For future work, we consider developing of new navigation system by connecting above image processing technique with AIS, and radar system.