It was intended to find a way to improve the earthquake resistance performance more effectively through various reinforcement methods regarding between the cabinet bottom and concrete slab, which is a vulnerable connection part in the event of an earthquake. In order to improve the earthquake resistance performance of an electric cabinet, methods such as installing a vibration isolation device, increasing the number of connecting bolts between cabinet bottom panel and base channel, welding a steel grid of cabinet bottom panel, etc. were considered and, in order to compare the performance of each case, a three-axis shaking table test was performed. As a result of comparing the seismic performance of each case according to the acceleration response, it was found that the reduction of seismic force was the best when applying the vibration isolation device. However, there is a disadvantage in that the spatial and temporal limitations are large and the unit price is high in field application. For this reason, it is predicted that a method of ensuring the higher rigidity of an electric cabinet by increasing the number of connecting bolts proved through this study would be a more economical and realistic seismic performance method in field application.