In order to ensure the safety of 400,000 DWT carrier entering and leaving Caofeidian port, the propagation law of tidal waves in the Bohai Sea is studied by using ADCIRC tidal level mathematical model. The tide level of 400 000 DWT carrier in the Bohai Sea super-long deep water route is calculated by multi-station joint calculation method, combined with the ship navigation mode. The results show that the tidal level of 400 000 DWT carriers is 1.0 m when it enters the harbor under the condition of 90% guarantee rate and 8 hours tide ride, and the tidal level is 0.2 m when it departures under the condition of 90% guarantee rate and 8 hours tide ride. That means the tide level corresponding to the same tide ride duration and cumulative frequency is obviously higher than that of the outbound. The tidal water level calculated jointly by Multi-stations is higher than that calculated by single tidal station; the outbound tidal level is less than the level calculated by single tidal station.