The prediction of ship motion is significant for ship navigation, but there is no effective solution to the ship pitching problem so far, and Time Series, Period Graph Method, Neural Networks and Grey System Theory were used to study the motion of a ship. 以往曾有人利用时间序列法、周期图法、神经网络法及灰色系统理论等方法来研究船的运动.目前还没有一种有效的方法解决船的纵摇。