Abstract: An automatic container coupling tool is disclosed, such coupling tool includes a coupling platform, a bottom engager and a top guiding protrusion oppositely extended from the coupling platform, the bottom engager has an engager neck, a pair of projecting lug extended from the engager neck to form a pair of holding cavity between the coupling platform and the projecting lugs, once the bottom engager is inserted into a corner fitting housing of a lower container, the bottom engager is rotated allowing the ceiling wall inserted into the holding cavity.