The turntable bearing is a large bearing capable of carrying on a larger load such as large axial load, radial load, overturning moment and other integrated load. It sets support, rotation, transmission, fixing and other functions in a special structure. In general, the turntable bearing has its own mounting hole, lubricating oil and sealing device to meet different needs of the various types of host under a variety of different working conditions. On the other hand, the turntable bearing has the compact structure, the easy steering rotation, the easy installation, the easy maintenance and other characteristics. And it is widely used in lifting transport machinery, excavators, construction machinery, port machinery, wind power, medical equipment, radar, missile launchers and other large rotary devices.