Abstract: Ruhr Pump is installed with NU series bearings. The original bearing disassembling method takes a long time and can do harm to the diameter of bearings. In order to disassemble bearings in a safe and quick way, 4 different bearing disassembling methods are compared in terms of disassembling time, damage to the bearing, difficulty in operation, risks and costs, and finally, heating ring bearing disassembling method is decided to be the optimal scheme. Through the selection of the material of heating ring, determination on the amount of the needed thermal expansion for disassembling of the bearing cone, and calculation on heat capacity of bearing cone and heating ring, the heating temperature and size of the heating ring are picked up. The design of nut-screw regulating mechanism and the expansion joint limit is improved to realize the adjustability of the heating ring diameter. And by this way, the bearing of the heating ring device can be disassembled quickly with no damage to the diameter of the bearing, which is worth popularization.