The mechanism structure of horizontal pipes connector was designed in order to connect two pipes in deep sea. The contact property of mechanics and sealing ring between the two flanges was analyzed, which was used finite element method, and obtained permissible compressive force and displacement of the sealing ring to realize sealing. The result is that the metal sealing ring allows the largest compression displacement of the metal sealing ring is 2 mm. It is accurately required to control the displacement of the pistons of hydraulic cylinders that push the flange.