The invention discloses a detachable berthing tool which comprises a leaning target diagonal bracing and a connecting pipe. One end of the connecting pipe is fixedly connected with the oblique plane of the leaning target diagonal bracing, the other end of the connecting pipe is fixedly connected with a main ship body structure of an installed ship, the bottom surface of the leaning target diagonal bracing is put on a bilge portion outward-extending structure of the installed ship, the leaning target diagonal bracing is fixed to the ship through the connecting pipe, the fixing points of the ship and the connecting pipe are located above the water surface, and marine berthing tool dismounting can be achieved. After the ship is built, the berthing tool can be still kept for ship towing and berthing usage during sea testing of the ship, and the problem that due to the fact that the fixing points of the ship and the connecting pipe are located above the water surface, the ship is needed to be berthed on a dock or a semi-submersible barge for berthing tool dismounting before trial voyage, ship towing is difficult, and the ship cannot be automatically berthed after trial voyage.