The invention provides an acetylene sludge aerated concrete block, which is prepared by processing the following raw materials in part by weight: 20-30 parts of acetylene sludge, 25-30 parts of coal ash, 5-10 parts of cement, 4-6 parts of modified attapulgite, 5-10 parts of water treatment sludge, 5-10 parts of soda residue, 5-10 parts of light calcium powder, 10-15 parts of lime, triethanolamine, 4-5 parts of gypse, 0.02-0.08 part of aluminium powder, oxidized paraffin wax soap, 0.01-0.02 part of calcium bicarbonate, 2-3 parts of chelky slag, 1-2 parts of lignocellulose, 0.3-0.5 part of water glass, 0.03-0.05 part of borax, 1-2 parts of sodium hexametaphosphate, 1-2 parts of hydroxy propyl methyl cellulose sodium and 1-2 parts of superfine polyvinyl alcohol, wherein the weight of the triethanolamine is 0.1-0.3 percent of that of the lime, and the weight of the oxidized paraffin wax soap is 3-5 percent of that of the aluminium powder. According to the invention, the acetylene sludge is added into the raw materials of the aerated concrete block, and meanwhile other conventional additives and modified nano additives are added; the aerated concrete block is prepared by adopting a proper technology and is low in cost and good in performance; the circulating economy effect of changing waste into valuable is realized; the pollution is reduced; and the prepared aerated concrete block has the characteristics of light volume weight, high thermal insulation performance, good sound absorption effect and high strength and can be used for non-bearing or bearing wall bodies.