The　chemical　compositions　of　the　sludge　after　treatment　are　tested　by　fully　chemical　analysis　techniques.　Its　crystalline　phase　structure　changes　of　the　sludge　calcined　at　different　temperature　are　characterized　by　XRD　method.　Nitrogen　gas　isothermal　adsorption　method　(77　K)　is　applied　to　measure　the　influences　of　ammonium　bicarbonate　on　specific　surface　area　and　pore　structure　of　activated　alumina　synthesized　from　waste　aluminum　sludge.　The　result　shows　that　the　amount　of　Al2O3　in　the　sludge　accounts　for　more　than　94%,　and　Na2Owt%　in　a　0.1-0.2%　range.　By　calcining　raw　sludge　at　600°C,　monophase　γ-Al2O3　is　obtained.　And　this　can　satisfy　the　performance　requirements　of　activated　alumina　adsorbent.　The　specific　surface　area　of　the　specimen　with　NH4HCO3　added　has　expanded　from　179　to　249　m2/g　and　the　pore　volume　from　0.25　to　1.11　cm3/g　as　well　as　the　average　pore　diameter　from　5.6　to　17.8　nm.　All　these　show　that　NH4HCO3　is　an　effective　pore-expansion　agent　to　remarkably　improve　the　structure　and　performance　of　activated　alumina　synthesized　from　waste　aluminum　sludge.