The single-row four-point contact ball slewing bearing consists of two seat rings, featuring compact structure, light weight, four-point contact between the steel ball and the arc roller path. It can bear the axial force, overturning torque and big radial force simultaneously, which is widely used in hoisting, transportation, construction machinery and military products. It can be used in the slewing type conveyor, welder, medium/compact hoisting machinery and excavators.