The development of modern industrial robots has the trend of lightweight and long life. Bearings should be installed in limited space, thus bearings must be small in volume and light in weight. Meanwhile, robots have high load, high rotation accuracy, high operation stability, high positioning speed, high repeatability positioning accuracy, long life and high reliability, which requires robot bearings to have high bearing capacity, high precision, high rigidity, low friction torque, long life and high reliability. Angular contact ball bearing, harmonic drive bearing, roller bearing, cross bearing can be used on industrial robot, which has worked well.