A dynamic indication system based on meteorological and hydrologic information is presented in the paper, which can help the naval ships commanders know weather and sea conditions at present time and in the future visually, and the safe navigation can be obtained. Using the information from weather and ocean forecasting organizations to show meteorological and hydrologic information in the sea area where the ship can reach in 24h and 48h, the commanders can know the weather and sea conditions in 2 days. According to the navigation safety statistics of different ships under different conditions, safety assessment on the courses to target sea area within 2 days of concerned ships can be made based on the theory and technique of risk analysis. The result of actual simulation shows that this system can be used to make safety assessment for ships’ courses objectively and quantitatively, and present safety index of the course, and provides important basis of scientific decision making for commanders to choose most suitable ship and course to perform the mission.