How to install a model line on the tank joint is disclosed. A method of installing the model line in the opening formed in the upper tank joint, model production line at the top step of the production if the model line to match the test waterline; Model line moving step of moving the line model produced in the model production step into the common line to the tank through the opening; Pairing Pairing plate installation steps to install the plate (Fairing plate) consisting of a single plate shape in the opening; And installing the model line to the common water tank to the model top surface line characterized in that it comprises a model line contact step of the bottom surface and the adhesion of the paired plates are produced the model line by matching with the test water line a model line of top face and to reduce the cost and effort required to. In addition, the paired plate is made of a single flat plate-like in as the bottom surface is in close contact with the model line of the top face pairing plate may be used semi-permanently, regardless of the model line shape, can be reduced manufacturing cost and effort of the paired plates. In addition, according to the model line and the cavity in yirueojim tank coupled pair of plates, it becomes unnecessary a separate working space for installing the plate pair in the model line, and to reduce the movement cost. Co-tank, model line, paired plate