Structural　change　of　iron　and　manganese　oxide　sludge　which　were　calcined　in　air　at　different　temperatures,　was　analyzed　by　X-ray　powder　diffraction,　transmission　electron　microcopy,　differential　thermogravimetry　and　nitrogen　adsorption　analysis　for　specific　surface　area,　respectively.　And　also　the　adsorption　behaviors　towards　As　was　investigated.　The　results　show　that　the　iron　and　manganese　oxide　sludge　is　amorphous　structure,　with　high　efficiency　of　arsenical　removal,　due　to　its　characteristics　of　small　particle　size　and　big　specific　surface　area.　Crystallization　water　beganto　lose　at　150,　and　specific　surface　area　and　pore　volume　had　a　little　change,　with　As　(III)　and　As　(V)　removal　rate　increased　slightly　corresponding.　Dehydroxylation　reaction　at　500　made　the　micropores　gradually　merge　into　mesopores,　leading　to　the　decrease　of　specific　surface　area,　and　further　dramatically　decrease　of　As　(III)　and　As　(V)　removal　rate　by　30%　of　the　original　value.　As　the　temperature　rising　to　800,　the　micropores　and　mesopores　gradually　merged　into　macropores,　resulting　in　the　increase　of　the　average　pore　diameter　by　10nm,　and　the　reduce　of　the　specific　surface　area　and　pore　volume　to　12.755m2/g　and　0.052cm3/g,　meanwhile　the　sintering　phenomenon　generated　between　hematite　crystal　particles,　which　made　the　removal　rate　of　As　(III)　and　As　(V)　plunge　to　about　10%　of　the　original　value.　©　2017,　Editorial　Board　of　China　Environmental　Science.　All　right　reserved.