Three-row roller slewing bearing, is a type of turntable bearing with high loading capacity, and is mainly used in heavy loading operation surroundings. It is composed of three rings, of which upper and lower and radial raceway are separated respectively, so that loading of every row roller can be decided. There exists adjusting shim between upper and lower rings, to adjust axial clearance. Upper and lower row rollers are set horizontally, to bear axial force and tilting moment from two directions. The third row roller set vertically bears radial force, so three-row roller slewing bearing can at the same time bear kinds of loading. Its loading capability is the greatest among four products, especially suitable for heavy machinery requiring large working diameter, for example, bucket-wheel excavator, wheeled crane, ship crane, ladle turret and heavy-duty auto crane, etc.