Aluminum-anodizing sludge (AAS), generated during the treatment of acidic waste-water in aluminum-anodizing process, is a kind of solid waste usually stockpiled due to low utilization. The recovery of aluminum and calcium from AAS through physicochemical process was systematically investigated in this paper. Phase analysis of AAS indicates that the Ca-bearing phases were CaCO 3 and CaSO 4 •2H 2 O, and the Al-bearing phases were amorphous Al 2 O 3 and Al(OH) 3 . The experimental results show that the readily soluble 3CaO•3Al 2 O 3 •CaSO 4 was formed by sintering the AAS, while the presence of silica caused the generation of insoluble 2CaO•Al 2 O 3 •SiO 2 . Under the optimal conditions, more than 93% of Al 2 O 3 in sintering product could be recovered by leaching in the mixed Na 2 CO 3 -NaOH solution. CaCO 3 and 2CaO•Al 2 O 3 •SiO 2 in leaching residue were efficiently separated by gravity separation, and approximately 89% of CaO in the leaching residue was enriched in the concentrate. The obtained sodium aluminate solution could be used for alumina production, and the concentrate with main phase of CaCO 3 could be recycled to treat acidic waste-water generated from aluminum-anodizing process.