The aim of this study was to find a way to improve earthquake resistance performance more effectively through various reinforcement methods between a cabinet bottom and concrete slab, which is a vulnerable connection in the event of 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 the cabinet bottom panel and base channel, welding a steel grid to the cabinet bottom panel, and so on, were considered and, in order to compare the performance in 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 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 for application in the field. For this reason, it is predicted that the method of ensuring the higher rigidity of an electric cabinet by increasing the number of connecting bolts, as proved through this study, would be a more economical and realistic seismic performance method in field applications.