The　primary　goal　of　this　research　is　frequency　analysis　of　the　spatial　flexible-rigid　coupled　parallel　manipulator.　A　new　model　of　spatial　flexible　beam　element　is　proposed.　The　dynamic　equation　of　the　spatial　flexible　beam　element　is　derived　based　on　the　finite　element　theory　and　Lagrange　equations.　The　kinematic　constraint　conditions　of　the　movable　platform　and　the　sub-chains　of　the　flexible-rigid　coupled　parallel　manipulator　are　derived,　based　on　the　elastic　displacements　of　the　movable　platform　and　the　sub-chains.　The　dynamic　model　of　the　movable　platform　is　developed　based　on　the　Newton-Euler　principle.　By　using　the　kinematic　constraint　equations　and　dynamic　model　of　the　moving　platform,　the　overall　system　dynamic　equations　of　the　flexible-rigid　coupled　parallel　manipulator　are　obtained　through　assembling　the　dynamic　equations　of　elements.　Then,　the　natural　frequencies　of　a　3-RRS　flexible-rigid　coupled　parallel　manipulator　are　studied　through　numerical　simulation.　From　the　simulation　results,　the　natural　frequencies　are　relatively　sensitive　to　the　structure　size,　section　parameter,　and　characteristic　parameter　of　material　on　mechanisms.　The　results　provide　important　knowledge　to　researchers　to　the　dynamic　analysis　and　optimal　design　of　flexible-rigid　coupled　parallel　manipulators.　©　2011　Journal　of　Mechanical　Engineering.