Bearing is an important part of contemporary machinery equipment. Its main function is to support the mechanical rotating body, to reduce the friction coefficient during its movement, and to ensure its rotation accuracy. According to the different friction properties of moving components, bearings can be divided into two categories: rolling bearings and sliding bearings. Rolling bearing has been standardized and serialized. But compared with the sliding bearing, its radial size, vibration and noise are bigger, the price is higher.