The invention relates to a power rat hole device of a marine drilling platform. A righting device between the upper round pipe and the lower round pipe of the power rat hole device comprises a slewing bearing; the slewing bearing comprises a slewing bearing internal fixing ring and a slewing bearing external slewing ring which are connected with each other through balls; a reciprocating rack is meshed with the slewing bearing external slewing ring and connected with a hydraulic cylinder; fixing shafts are mounted on the slewing bearing internal fixing ring; rotating shafts are mounted on the slewing bearing external slewing ring; upper righting plates and/or lower righting plates are mounted on the upper end surface and/or the lower end surface of the slewing bearing; the upper righting plates and/or the lower righting plates are in rotational connection with the fixing shafts and are connected with the slewing bearing external slewing ring through the rotating shafts; notches are formed in the upper round pipe and the lower round pipe in positions corresponding to the upper righting plates and/or the lower righting plates. The power rat hole device solves the difficult problem that a power rat hole in the current automatic drill string operating system of a drilling platform rights a drill pipe and receives/unloads three-joint units frequently during production operation, thereby greatly improving the drill pipe processing efficiency of the automatic drill string operating system.