UWE double row different diameter ball slewing bearing is mainly made up of in-up ring, in-down ring and outside ring, so balls and spacers can be directly discharged into the upper and lower raceway. According to stress conditions, bearings are arranged to two rows of balls of different diameter. This assembly is very convenient. Angle of both upper and lower raceway is 90°so bearings can bear large axial force and resultant torque. Bearing needs special design when radial force is 0.1 times larger than the axial force. Large in sizes and features compact in design, bearings are particularly application in handling equipments requiring medium above diameter, such as tower crane and mobile crane.