This paper investigated the effects of stone powder sludge on the flow, density and strength properties of AAC (autoclaved aerated concrete) samples. Stone powder sludge prodeced from crushed aggregate factory was used to investigate the suitability as a substitute for quartz sand. To determine the properties of AAC mixes with stone powder sludge, AAC specimens containing different foam ratios were produced. Flow, density, compressive strength, tensile strength and flexural strength of the samples were measured, and X-ray diffraction (XRD) also was performed. The test results indicated that adding water content of 35% was suggested as the optimal amount of water to obtain proper fluidity for making AAC mix with stone powder sludge. For same foam ratio of 120%, the compressive strength of F120 specimen with stone powder sludge was higher than that of the Q120 specimen with quartz sand. For all XRD diagram, a higher number of tobermorite peaks was shown for the F120 sample than for the Q120 sample, which may explain the slightly higher strength gain in the F120 sample.