A mechanical model of the rotor of high-speed motor is proposed. The differential equations and their special solutions are also offered in this paper. To the cantilevered end of this rotor an alterating interference force is applied.The mechanism that parallel plain thrust bearing can be used in the rotor-bearing system for journal bump foil bearing is theoretically revealed.The running test indicates that the performance of the open-end spinning machine driven by the high-speed motor using bump foil bearings is highly satisfactory, and the quality of the yarn completely accords with the quality index set up by the state.It is verified by both theory and practice that this rotor-bearing system, to which small thrust load is applied, is suitable for small load and high-speed machine with cantilevered end.