The　Ce-Cu-SAPO-18　catalysts　were　prepared　using　the　ion　exchange　method.　The　impact　of　sulfur　dioxide　on　catalytic　performance　of　Ce-Cu-SAPO-18　for　the　selective　catalytic　reduction　(SCR)　of　NO　with　NH(3)was　examined.　Detailed　characterization　of　the　fresh　and　sulfur-poisoning　Cu-SAPO-18　and　Ce-Cu-SAPO-18　samples　was　conducted.　XRD　and　BET　results　show　that　SO(2)treatment　of　the　Ce-doped　Cu-SAPO-18　(Ce-Cu-SAPO-18-S)　sample　did　not　induce　a　remarkable　change　in　structure,　as　compared　with　that　of　the　fresh　counterpart.　According　to　in　situ　DRIFT,　H-2-TPR,　SEM,　and　EDS　results,　it　is　found　that　the　sulfation　species　attached　preferentially　to　the　cerium　species,　rather　than　the　isolated　Cu(2+)species.　In　particular,　the　TG/DSC　results　confirm　that　the　sulfate　species　on　the　Ce-Cu-SAPO-18-S　sample　was　easier　to　decompose　than　that　on　the　Cu-SAPO-18-S　sample.　The　catalytic　active　sites　of　Ce-Cu-SAPO-18　were　less　influenced　after　SO(2)treatment,　as　demonstrated　by　the　TPR　and　XPS　results.　All　of　the　above　results　show　that　the　Ce-Cu-SAPO-18　sample　exhibited　better　sulfur-resistant　performance　than　the　Cu-SAPO-18　sample.