In Japan, the development of large high speed vessel has been carried out. That large high speed vessel is expected to run even in congested water area. If the vessel starts her service in congested water area the collision risks will be higher than now. So it is urgent problem to develop navigation system which ensure the safety of navigation of the large high speed vessel, to develop useful evaluation method of such navigation system and to evaluate and confirm the effectiveness of the system. In this paper an evaluation method of navigation system of large high speed vessel with simulator experiments is discussed and an index which is used for evaluation of the effectiveness of navigation system by measuring safety of navigation and was obtained by simulator experiments is shown.