The　RF　switches　were　fabricated　based　on　microelectromechanical　techniques.　For　good　RF　performances,　the　precise　control　is　needed　over　the　contact　separation　when　switch　is　open　and　over　the　contact　force　when　the　switch　is　closed.　In　this　paper,　the　optical　interference　technique　has　been　applied　to　make　the　accurate　measurement　of　the　contact　position　and　the　height　distribution　of　the　actuators.　The　shape　changes　of　switches　can　be　observed　in　original　shape　and　in　actuated　state.　The　results　were　compared　with　the　scan　electronic　microscope　(SEM)　measurement.　(C)　2004　Published　by　Elsevier　Ltd.