A　symmetrical　deployable　coupled　mechanism　with　one　translational　degree　of　freedom　(DOF)　is　proposed　based　on　the　particularity　and　symmetry　of　a　regular　dodecahedron.　According　to　the　spatial　arrangement　of　all　component　geometrical　elements　in　a　regular　dodecahedron,　the　construction　of　coupled　framework　is　established.　All　component　parts　can　be　defined　and　motion　chains　can　be　obtained　correspondingly.　Three　types　of　substitutive　components　are　designed　on　the　basis　of　the　merging　condition　of　above　defined　parts　in　coupled　framework.　The　equivalent　geometrical　model　is　spliced　with　the　given　substitutive　parts　just　by　rotation　joints　(R).　The　DOF　of　the　model　is　calculated　and　the　output　motion　is　analyzed　under　the　condition　that　the　elementary　loop　corresponding　to　a　regular　pentagon　in　a　regular　dodecahedron　is　movable.　The　expected　symmetrical　coupled　mechanism　can　be　established　based　on　the　mobility　analysis　of　the　entire　model.　The　three-dimensional　SolidWorks　model　of　the　coupled　mechanism　is　build.　The　displacement　variations　of　the　end　and　nodes　under　different　driving　conditions　are　simulated　and　revealed　with　time-displacement　curves　by　Matlab.　Simulation　results　show　that　the　novel　mechanism　is　a　symmetrical　deployable　coupled　mechanism　with　one　translation　DOF.　©　2018　Journal　of　Mechanical　Engineering.