In　this　study,　we　investigated　the　problem　of　designing　a　human-knee　self-adaptive　exoskeleton　mechanism.　From　the　test　data　of　a　knee-joint　flexion　experiment,　we　extracted　instantaneous　helix　parameters　of　knee-joint　motion.　Given　the　physiological　structure　and　the　helical　axis＇s　transient　characteristics　of　the　knee-joint,　we　established　a　knee-joint　kinematics　model.　Then,　considering　the　kinematical　compatibility　between　humans　and　machines,　we　performed　a　freedom　analysis　of　the　human-machine　closed　chain　and　the　human-machine　constraint　moment　properties.　In　this　paper,　we　propose　a　novel　configuration　for　a　knee　exoskeleton　mechanism,　which　is　compatible　with　the　human　knee　joint.　With　the　goals　of　structural　simplicity　and　comfort　to　the　wearer,　we　designed　a　novel　rehabilitation　exoskeleton　device　for　the　knee　complex,　including　the　design　of　an　exoskeleton　body　and　a　specific　wearable　jig.　The　proposed　human　knee　exoskeleton　enables　ideal　self-adaptation　to　the　human　knee　axis.　©　2017,　Editorial　Department　of　Journal　of　HEU.　All　right　reserved.