Abstract： To study the accessibility of large ships, a computational model for emergency evacuation was established based on the differences between naval ships and passenger ships. The minimum evacuation time and optimal watertight are two goals of the model. By using genetic algorithms, the evacuation routes for functional groups in different locations were calculated and selected, considering the capacity constraints and influence of encounter flow and counter flow. The comparison with the method based on the shortest path implied that the shortest path is not necessarily the optimal path of ship evacuation.