The research process of the adjustment plan of the Dalian Bay water area under the influence of a cross-sea traffic project was introduced in this paper. According to the navigation environment in the Dalian Bay water area，the development trend of the port and related industries was analyzed and the representative ship types of navigation in each port area were predicted. Using the design scheme of the north bridge and south tunnel of the Dalian Bay cross-sea traffic project as boundary conditions，according to the conditions and navigation requirements of the bay waters，the safe distances between bridge and anchorage，bridge and channel boundary were reasonably determined by introducing the factor of representative navigation vessel length with certain assurance rate. Three solutions for the adjustment plan were given and compared. Issues that needed to be paid attention to during the subsequent implementation stage were put forward.