Abstract: During the regular inspection process of a certain type of engine, it was found that the bearing clearance exceeded the standard. After disassembly, analysis and investigation, it was found that there were signs of wear on the outer steel sleeve and ball of the intermediate bearing. The reason was that the residual magnetism of the outer steel sleeve exceeded the standard, adsorbing the ball and causing the ball to move from rolling to sliding, seriously affecting the safe operation of the engine. Therefore, this paper mainly discussed the reasons and control methods for the residual magnetism exceeding the standard of the intermediate bearing in aviation engines. We sorted out all the links that can generate strong magnetic fields between magnetic particle testing and assembly of intermediate bearings, analyzed the reasons for the excessive residual magnetism, and developed improvement measures through experiments to ensure that the residual magnetism of the installed intermediate bearings was within the standard range.