A microelectromechanical systems (MEMS) isolation amplifier is presented, which uses MEMS switches to realize a "flying capacitor" structure. This isolation amplifier has the advantages of simple circuit structures, smaller dimensions, low cost, excellent electromagnetic compatibility (EMC) performance, easy to make multichannel isolation circuits, integration compatibility with on-chip electronics, etc. The performance of the MEMS switch exhibits 30-V pull-in voltage, 35-μs time delay, and 110-V breakdown voltage. The preliminary performance of the isolation amplifier is also demonstrated. To our knowledge, this work presents the first MEMS isolation amplifier structure.