Aerated concrete was prepared by alkali activated steel slag and blast furnace slag with hydrogen peroxide as air entraining agent. The influence factors on the performance of aerated concrete, including steel slag content, blast furnace slag content, molar ratio of water glass, alkali content, water binder ratio and the alkali solution temperature were investigated. The microstructure was characterized by XRD, SEM and FTIR. Results show that to produce the aerated concrete with optimum properties, the content of steel slag is 40% with blast furnace slag of 60%, and molar ratio of water glass is 16, the alkali content is 6%, and water binder ratio is 042, hydrogen peroxide content is 4% and 8%. The alkali solution temperature should be at 30℃. Pore size for B06 and B05 products are ranging from 03 to 06mm and from 05 to 10mm, and the pore are mostly closed holes with a uniform circular shape. Maintenance methods have no effect on the type of hydration products. Microstructure analysis show that the main hydration products are C S H gel and C A S H gel. The physical and mechanical properties of B06 product can meet the requirements of the standard GB 11968—2006 with steam curing.