According to the setting theory of liquid friction: between the relative movement, if it bears the load and still ensures the oil film’s existence, the two planes must form the wedge, and the movement direction must from wide to narrow and the lubrication should be adequate and has viscosity. The journal which puts into the bearing bush will form the wedge clearance. When the journal rotates, it will form the relatively movement with the bush, the journal rotates will bring in the lubricating oil which has the pressure and viscosity from the bearing pedestal to the bush. The oil will adhere to the oil neck and rotates with the oil neck. It will constantly bring the lubricating oil to the wedge clearance. Because the lubricating oil inflowing into wedge clearance which from the wide is more than the oil from the narrow. The oil accumulates in the wedge clearance and form the oil pressure. When the oil pressures surpass the oil neck’s gravity, it will lift up the journal and it will form the interval between the bush and the journal. The lubricating oil is in here. The liquid friction is formed.