Based on the vibration waveform, frequency spectrum and phase, the vibration characteristics of two kinds of loose faults of rotary auxiliary machinery in thermal power plant are analyzed, so as to determine the fault location accurately. The treatment method adopted in this paper is as follows: tighten the anchor bolt of the #2 feed pump and lubricate the bearings of the free end and drive end of the #2 feed pump. After processing, the maximum three-axial vibration of the non-drive end of the motor is reduced from 3.28 to 0.139 mm/s, the maximum three-axial vibration of the motor drive end is reduced from 2.95 to 0.245 mm/s, and the maximum three-axial vibration of the fan drive end is reduced from 2.9 to 0.277 mm/s. Combined with the actual case application, the analysis method and governance results show that the method provided in this paper is simple and effective.