Fabrication　technology　of　radio　frequency　microelectomechanical　system　(RF　MEMS)　in　series　was　studied.　The　fixed-fixed　beam　structures　were　used　in　the　switches,　which　consist　of　SiN　suspending　membranes　grown　by　plasma　enhanced　chemical　vapor　deposition　(PECVD),　coplanar　wave-guide　coated　with　gold　film,　and　a　polyimide　sacrificial　layer　released　by　O2　plasma　etching.　The　fabrication　of　SiN　membrane,　the　electrodes　and　the　coplanar　waveguide　were　discussed　respectively.　And　how　the　growth　of　the　sacrificial　layer　and　the　chemical　etching　affect　the　performance　of　switches　was　also　discussed.