The　ankle　rehabilitation　robot　is　essential　equipment　for　patients　with　foot　drop　and　talipes　valgus　to　make　up　deficiencies　of　the　manual　rehabilitation　training　and　reduce　the　workload　of　rehabilitation　physicians.　A　parallel　ankle　rehabilitation　robot　(PARR)　was　developed　which　had　three　rotational　degrees　of　freedom　around　a　virtual　stationary　center　for　the　ankle　joint.　The　center　of　the　ankle　should　be　coincided　with　the　virtual　stationary　center　during　the　rehabilitation　process.　Meanwhile,　a　complete　information　acquisition　system　was　constructed　to　improve　the　human-machine　interactivity　among　the　robot,　patients,　and　physicians.　The　physiological　motion　space　(PMS)　of　ankle　joint　in　the　autonomous　and　boundary　elliptical　movements　was　obtained　with　the　help　of　the　RRR　branch　and　absolute　encoders.　The　natural　extreme　postures　of　the　ankle　complex　are　the　superposition　of　the　three　typical　movements　at　the　boundary　motions.　Based　on　the　kinematic　model　of　PARR,　the　theoretical　workspace　(TWS)　of　the　parallel　mechanism　was　acquired　using　the　limit　boundary　searching　method　and　could　encircle　PMS　completely.　However,　the　effective　workspace　(EWS)　was　smaller　than　TWS　due　to　the　physical　structure,　volume,　and　interference　of　mechanical　elements.　In　addition,　EWS　has　more　clinical　significance　for　the　ankle　rehabilitation.　The　PARR　prototype　satisfies　all　single-axis　rehabilitations　of　the　ankle　and　can　cover　most　compound　motions　of　the　ankle.　The　goodness　of　fit　of　PMS　can　reach　93.5%.　Hence,　the　developed　PARR　can　be　applied　to　the　ankle　rehabilitation　widely.