Abstract: Wind-assisted ship is an effective way for energy-saving and emission reduction and by the using of ocean winds effectively, it is very useful for transoceanic crossings to cut down fuel costs, this study focuses on route optimization to minimize the fuel consumption of wind-assisted ships. Firstly, by the analysis of monthly means speed of ocean winds, it was found that the wind-assisted propulsive efficiency was high as auxiliary power. Secondly, the ship route was discretized to a series of waypoints which can be considered small deviations to generate a new route and the “minimum fuel consumption” was taken as optimization objective, then the optimization model was built based on ship motion equations. Thirdly, based on the simulated annealing algorithm, the optimal route searching strategy was designed and the model was solved. At last, a 76, 000 DWT wind-assisted cargo ship was taken as the experimental ship and the optimization algorithm was simulated and verified by an optimized wind-assisted route. As the simulation shows, the optimization effect is satisfactory, so the route optimization algorithm designed in this paper can be applied to the solving of path planning problem of wind-assisted ship and thus provides theoretical guidance to further study on wind-assisted projects.