Abstract: In this paper, a compound was made from copper tailing and polishing mud to replace fly ash and then add the cement, lime, gypsum and other materials to prepare the autoclaved aerated concrete. The influence of particle fineness, dosage and technological parameters on the compressive strength and dry density of autoclaved aerated concrete block was studied. The microscopic mechanism was studied by XRD and SEM. The experimental results showed that when copper tailing and ceramic polishing mud were grinding for 20 min, the surface area of copper tailing and ceramic polishing mad were 244.5 m²/kg and 350.4 m²/kg. With the mixing ratio of raw materials for copper tailings was polishing mud∶cement∶lime∶gypsum=45∶20∶10∶22∶3, the maximum compressive strength of the block reached 5.1 MPa, the average compressive strength reached 4.7 MPa, and the dry density was less than 625 kg/m³, complete complied with the requirements of autoclaved aerated concrete block of A3.5 B06. Tobermorite, C-S-H(B) and other hydration products in the block was closely interposed with unreacted quartz, which made the microcosmic pore structure of the block more compacter and the compressive strength higher.