Based on marine protection works of Pakistan deep-water container port, this paper introduces three-dimensional visible installation system POSIBLOC which consists of five systems with six functions. Combing with practical application in placing armor units Core-Loc in the project, this paper describes its three advantages: POSIBLOC can show the location, direction and orientation in real time due to its visibility and three-dimensional imaging function which can guarantee the construction quality; POSIBLOC adopts double GPS for positioning, and provide continuous, highly precise, three-dimensional location, speed and time information in real time, combined with its target-indication function to improve placing precision; By POSIBLOC, diver checking can be cancelled to shorten idling time, and site work can be executed 24 hours to improve the placing efficiency.