An autoclaved aerated concrete block produced from sludge and carbide slag belongs to the fields of environmental protection and building materials. Raw materials for producing the autoclaved aeratedconcrete block comprise 25-45 wt% of carbide slag, 25-35 wt% of sludge, 15-30 wt% of silica sands, 6-12 wt% of cement clinker and 3-6 wt% of natural gypsum, and a water reducer accounting for 0.6-0.9%of the total mass of the above obtained dry material mixture, aluminum powder accounting for 0.06-0.12% of the total mass of the dry material mixture and 48-55 DEG C warm water accounting for 35-45%of the total mass of the dry material mixture are added. The wet compressive strength of the autoclaved aerated concrete block produced in the invention reaches 3.5 MPa or more, the absolutely dry compressive strength reaches 5 MPa or more, the dry bulk density is 550-650 kg/m<3>, and the autoclaved aerated concrete block meets national standard requirements of the performance indexes of the autoclaved aerated concrete block, opens up a new utilization way for the sludge and carbide slag resources which are difficult to use, and facilitates the solving of the problems of land resource occupation and environment pollution caused by piling of the sludge and the carbide slag.