The mounting axial clearance of the aligning roller bearings can be adjusted by adjusting the adjusting nut on the journal, thread in the adjusting spacer and bore, or adjust with load spring and other methods. The size of axial clearance is related to the arrangement of the bearing during installation, the distance between the bearings, and the material of the shaft and the bearing seat, which can be determined according to the working conditions. For the high load and high speed roller bearing, the influence of temperature rise on the axial clearance must be taken into account when adjusting the clearance. In other words, the clearance reduction caused by temperature rise should be calculated. In other words, the axial clearance should be adjusted slightly larger. For bearings with low speed and bearing vibration, no clearance should be adopted or loaded installation that should be applied. The purpose of this paper is to make the roller and raceway of the aligning roller bearing which have good contact, and the load is distributed uniformly, so as to prevent the roller and raceway from being damaged by vibration impact. After adjustment, the size of axial clearance is checked by a dial gauge. The method is to fix the dial gauge on the fuselage or bearing seat, so that the dial contact can bear on the smooth surface of the shaft and push the shaft along the axial direction. The maximum pendulum momentum of the dial needle is the axial clearance value.