Abstract: In view of the phenomenon that the lifting bail pin shaft of 8SA top drive in the TDS series of an offshore drilling platform, rotates in the overhaul and dismantling, and the lifting bail pin hole of the box is eccentrically worn and expanded into an ellipse, the causes are analyzed. The advantages and disadvantages of two conventional repair methods of box pin hole are analyzed and compared, and the repair methods of lower box pin hole in top drive overhaul are given. Finally, from the perspective of design, the methods to fundamentally eliminate the eccentric wear of the pin hole of the top drive box are proposed and demonstrated. Some methods have been put into practice, aiming to provide reference for the upgrading and transformation of similar equipment in the future.