The invention provides a shaft sleeve locking mechanism which comprises a shaft, a shaft sleeve, a bearing inner ring, a bearing outer ring, rolling balls and a fixing pin. The upper surface of the fixing pin and the bearing inner ring are flush after the fixing pin is clamped into a groove, a slope is arranged on the fixing pin, an oblique upper direction of the slope and a rolling direction of each rolling ball are consistent, and an adjusting bolt can be screwed into a first threaded hole from a second threaded hole and are abutted on the outer convex surface of an extrusion portion. Shaft rotation is started by the mechanism, parts of rolling balls strike the front portion of the fixing pin sometimes when the rolling balls constantly pass the extrusion portion, so that the fixing pin is pushed to the groove, and the shaft sleeve, the bearing inner ring and the shaft are locked through shaft rotation.