In　this　paper,　the　hydrothermal　stability　and　catalytic　activity　of　Pd@Ce0.5Zr0.5O2/Al2O3　catalyst　with　a　core-shell　structure　were　investigated　for　automobile　three-way　reactions　and　compared　with　those　of　Pd/Al2O3,　Pd@CeO2/Al2O3,　and　Pd@ZrO2/Al2O3　catalysts.　TEM,　HRTEM,　and　EDS　mapping　analyses　showed　that　the　core-shell　structure　of　Pd@Ce0.5Zr0.5O2　nanoparticles　was　intact　after　the　hydrothermal　treatment　at　1050　degrees　C　for　S　h.　Meanwhile,　CO-DRIFT　results　suggested　that　the　interface　of　Pd　core　and　Ce0.5Zr0.5O2.　shell　acted　as　the　active　sites　in　the　reaction　of　three-way　catalysts.　Additionally,　XPS,　FT-M　and　CO-DRIFT　analyses　demonstrated　that　a　large　amount　of　OH　groups　were　present　on　the　surface　of　Pd@Ce0.5Zr0.5O2/Al2O3　catalyst,　which　could　accelerate　the　decomposition　of　carbonate　species　and　reduce　the　activation　energy　of　the　catalytic　reaction.　This　was　an　important　reason　for　the　Pd@Ce0.5Zr0.5O2/Al2O3　catalyst　to　keep　the　high　catalytic　activity　after　aging　at　high　temperature.