Abstract: The structure of modular metal seismic isolation bearing (MMSIB) is proposed and decoupled design method is developed. The effectiveness of MMSIB is verified using shaking table test of a current transformer (CT). The results show that MMSIB exhibits excellent isolation performance. The acceleration response at the top of CT can be reduced to 7.32%~32.57% of non-isolated specimen. The MMSIB has good self-centering ability with limited residual deformation. The actual residual deformation of MMSIB is less than the design value ignoring the input ground motion types and earthquake intensities. Sufficient anti-overturning ability provided by MMSIB satisfies the requirement of inter-layer seismic isolation of electrical equipment with supports. The vertical ground motion has negative effect on MMSIB that enlarges the horizontal deformation. The dynamic amplification effect of support and inherent capacity of electrical equipment should be considered in seismic isolation design. The design objective should be carefully determined to avoid reaching the ultimate deformation of MMSIB.