The failure of GIS equipment is primarily attributed to mechanical defects and insulation defects. At present, the research on mechanical defects primarily focuses on the characteristics of defects under a single external application current, lacking comparative studies on the GIS equipment’s vibration under the combined effect of voltage and current for different defects. To address this gap, this paper built a real 500 kV GIS experiment platform to investigate the vibrational properties under voltage ranging from 100 kV to 500 kV and current injection ranging from 1000 A to 5000 A. The tested defects included incomplete isolation switch stroke, loose bus contact base, foreign body, among others. Based on the above test results, it is concluded that under non-fault conditions, the frequency of vibrations in the GIS is twice that of both applied voltage and injected current. Furthermore, there is a superposition effect between current and voltage on the maximum value of the vibration signal. The characteristic of the bus bar defect is mainly manifested as an increase in the maximum value of vibration, and the isolation switch defect is the high frequency harmonics. For GIS equipment under operating conditions, typical defects in bus bar and disconnector can be identified by utilizing vibration characteristics.