Disclosed are an RF MEMS switch and a fabrication method thereof. According to an embodiment the RF MEMS switch is actuated with a low voltage and a low consumption power by using a piezoelectric capacitor actuated by being converted to mechanical energy from electric energy when an electric field is applied to the piezoelectric capacitor. A cap substrate can be formed by using an etching method, a chemical mechanical polishing method, an electroplating method, etc., and the RF MEMS switch has a high reliability and a high yield.