For　the　rehabilitation　needs　of　shoulder　joint　movement　disorder,　a　3R-PU　serial　shoulder　rehabilitation　exoskeleton　mechanism　is　proposed　to　realize　the　movements　of　abduction/adduction,　flexion/extension,　internal/external.　To　realize　human-machine　kinematic　compatibility,　the　human-machine　closed　chain　which　consists　of　the　exoskeleton　mechanism　and　the　upper　limb　is　translated　into　an　exact　kinematic　constraints　system　with　three　degrees　of　freedom　by　introducing　a　passive　sliding　pair　P　and　a　hooke　hinge　U　in　the　human-machine　interface.　Based　on　the　kinematic　coupling　analysis　of　related　joints　in　shoulders,　the　position　changes　relationship　of　the　center　of　glenohumeral　joint　(CGH)　relative　to　the　location　of　the　sternum　are　obtained.　The　angular　displacement　curves　of　kinematic　pairs　of　the　exoskeleton　mechanism　are　acquired　by　establishing　the　model　of　the　human-machine　closed　chain　and　solving　the　position　inverse　solution.　Furthermore,　the　velocity　Jacobian　matrix　of　the　human-machine　closed　chain　is　derived　and　the　kinematic　dexterity　is　analyzed.　The　results　show　that　the　motion　amplitude　of　passive　joint　P　and　U　are　larger　in　the　rehabilitation　training　process,　passive　joints　introduced　are　beneficial　to　release　motion　constraints　of　human-machine　interface,　and　then　the　constraint　intensity　of　human-machine　is　reduced.　Meanwhile,　this　exoskeleton　mechanism　has　better　kinematic　dexterity　when　the　upper　arm　is　elevated　at　0°,　45°,　90°　and　135°　lifting　surface.　The　above　research　results　will　provide　analysis　basis　for　the　exoskeleton　mechanism　motion　planning　and　control.　©　2018　Journal　of　Mechanical　Engineering.