Abstract: For the demand of the underwater security of the wharf, retrofitting the diver detection equipment would be feasible. The install location is confirmed based on the structural style of the wharf, hydrologic regime and the performance of equipment. After that, the structural design, fluid computation, thermal analysis and anticorrosive and antifouling design are carried out in order to guarantee the long-duration normal operation. The project is accepted smoothly, showing that the diver detection equipment retrofitted into wharf could satisfy the needs of dipping in water for long time and running normally.