Abstract: The present invention relates to a leak detection method for GIS based on vibration signals and belongs to the technical field of apparatus for detecting or reacting mechanical or electrical troubles. The method is carried out by the following steps: 1) Installing a vibration sensor on each connecting flange of each gas-tight chamber of the GIS; 2) Starting the GIS; 3) Acquiring the vibration signals of sensors when the GIS operation is stable after starting; 4) Doing de-noise processing on the collected vibration signal; 5) Doing 4-layer wavelet packet decomposition of the vibration signal after noise reduction to obtain the energy proportion of the vibration signal in each frequency band; 6) Analyzing the energy proportion of the vibration signal in each frequency band in step 5), Then alarm to notify the relevant personnel. Return to step 3) until the fault has been solved.