Abstract: The model for predicting ship's parametric rolling and synchronous rolling under complex sea and weather Conditions is introduced. This model is developed based on the multivariable-multi-constraint sea state model and navigational optimization model. The ship track is smoothed by using the priori knowledge on Coupling Characteristics of the variables in spatial distribution and time sequence. The model is used for navigation optimization in the sense of getting away from severe sea area and avoiding parametric rolling and synchronous rolling.