In view of the difficulty of accurate real-time survey of the coastal long-distance tide level during construction,we study the principle of real-time tide level observation during construction and the dynamic change of trailing suction vessel’s draft based on the dredging project of Lianyungang Port 300,000 DWT channel phase II project,and propose a method of surveying the coastal long-distance tide level based on the technology of satellite difference and verify it in dredging projects. This method meets the requirements of the current specification for port and waterway engineering survey and the accuracy requirement of the construction water level as well. Moreover,it is applicable to any sea area in the world,and it is worthy of popularizing in the real-time tide level measurement in coastal long-distance construction.