Heteropolyacids　and　their　salts　have　been　effectively　used　in　selective　catalytic　reduction　because　of　the　Keggin　structure　and　extraordinarily　strong　acidity.　Catalysts　with　and　without　the　Keggin　structure　were　synthesized　to　further　investigate　the　effects　of　heteropolyoxometallate　on　low　temperature　NH3-SCR.　XRD,　BET,　Raman,　H-2-TPR,　NH3-TPD,　FT-IR,　and　SO2-TPD　techniques　were　used　to　characterize　the　physicochemical　characteristics　of　the　catalysts.　Results　indicate　that　catalysts　with　the　Keggin　structure　had　more　surface　Bronsted　and　Lewis　acid　sites,　and　these　catalysts　had　significantly　improved　performances　in　the　SCR　reaction　and　in　SO2　poisoning　resistance.　[GRAPHICS]　.