The bearing is an important component of the steam turbine, and the main bearing is also called the radial bearing. Its function is to bear the full weight of the rotor and the centrifugal force caused by the imbalance of the rotor mass and to determine the correct radial position of the rotor in the cylinder. Since each bearing has to bear a high load and the journal speed is very high, the bearing of the steam turbine adopts the bearing-type sliding bearing based on the theory of liquid friction. With the help of a certain pressure of lubricating oil between the journal and the bearing An oil, the film is formed between them and liquid friction is established to make the steam turbine run safely and stably.