To ensure the navigation of yachts and water exchange in coastal areas, it is often necessary to build new locks or set up navigable structures such as navigable holes.With the intensification of marine ecological and environmental protection in recent years, the use of sea indicators has become more and more tense, and the traditional construction technology of large cofferdams on dry land is increasingly unable to adapt to the new situation.For this reason, this paper combines the basic engineering of Lianyun New City, and conducts research on key technologies such as structure selection, water and seepage prevention in view of the complex situations such as limited sea use, harsh natural conditions, riprap foundations and tight construction periods, and the design technology of prefabricated gate chamber and prefabricated wing wall are proposed, which can solve the relevant technical problems well and provide references for the design and construction of related projects.