Mechanical vibration signals of GIS equipment are important information to reflect the operating status of equipment, but the vibration excitation of existing research is mostly based on a single power frequency current, and the detection effect has certain limitations. Therefore, in order to explore the influence of current frequency on GIS mechanical vibration characteristics, this paper carried out research on GIS mechanical vibration characteristics under variable frequency current excitation. Firstly, the mechanical vibration simulation platform of 110 kV GIS equipment under variable frequency current excitation was built in the laboratory. Then, the vibration signals generated by the equipment shell under normal operation state were collected based on the mechanical vibration detection system. Finally, the evolution laws of time domain and frequency domain vibration spectra of GIS equipment under different current frequencies and loads were studied. The results show that the overall time domain waveforms are smooth and the main vibration frequencies are twice the frequencies of excitation currents. Under the condition of the variable frequency current excitation with the same amplitude, the amplitudes of time domain and frequency domain vibration spectra of vibration signals are the largest when the GIS equipment is excited by 1200 A current at 40 Hz and 2400 A current at 80 Hz. Under the condition of the variable amplitude currents excitation with the same frequency, the amplitudes of vibration signals are positively correlated with the amplitudes of currents, and the distributions of frequency spectra are highly concentrated.