The　reason　for　the　deactivation　of　catalysts　in　the　process　of　preparing　high　value-added　hydrogenated　nitrile　rubber　by　heterogeneous　catalytic　hydrogenation　of　nitrile　rubber　was　investigated.　It　was　found　that　the　cause　of　the　decrease　in　catalyst　activity　was　not　the　loss,　agglomeration　or　poisoning　of　noble　metal　nanoparticles.　The　reactants　could　not　contact　with　the　active　sites,　which　was　the　real　reason　for　the　reduced　activity.　Therefore,　the　effective　removal　of　the　polymers　from　the　active　sites　was　the　key　to　catalyst　regeneration　and　reuse.　Secondly,　based　on　the　similarity-intermiscibility　theory,　the　recycled　catalyst　was　treated　with　a　single　or　a　mixed　solvent　to　elute　the　polymers　and　recover　its　activity.　The　results　showed　that　the　catalyst　activity　could　be　restored　to　90%　of　the　fresh　catalyst　activity　by　washing　with　ethyl　acetate,　butanone,　N,N-dimethylfirmamide　or　N-methylpyrrolidone.　When　treated　with　a　mixed　solvent,　its　catalyst　activity　could　be　increased　to　95%　of　the　fresh　catalyst　activity,　and　could　remain　steady　after　recycling　4　times.　SEM　and　TG　characterization　results　showed　that　after　the　organic　solvent　regeneration,　Pd　active　sites　on　the　surface　of　the　catalyst　were　exposed,　thus　its　hydrogenation　activity　was　remarkably　improved.　©　All　Right　Reserved.