A fabrication method of an RF MEMS switch includes forming a signal transmission line having a first signal transmission line and a second signal transmission line electrically separated from each other for transmitting a signal and forming an on/off component for turning on/off the signal transmission line. The forming the on/off component further includes forming a suspension layer, forming a piezoelectric capacitor disposed at the suspension layers, and actuated with a piezoelectric characteristic by receiving an external power, forming a contact electrode disposed at the suspension layers, and electrically separated from the piezoelectric capacitors, and forming a ground line adjacent to the signal transmission line, wherein the ground line is electrically connected to the signal transmission line by a connection line.