Aerated concrete is a new type of building materials. Clayish crushed stones are regarded as solid waste disposals in China. This paper reports the research outcomes of an experimental study on using clayish crushed stone for the production of aerated concretes of B05 and B06 grade. Hydro-thermal synthesis reaction, mixing proportions, gas-forming and their influences on the concrete performance are investigated. Proper mixing proportions and some important technical parameters are proposed for material design. The microstructure of aerated concrete made with clayish crush stone is analyzed by means of X-ray diffraction (XRD) and scanning electron microscopy (SEM). The results indicate that the hydration products of clayish aerated concrete are composed of poor crystallized C-S-H (B), blade- and needle-shaped Tobermorite and a small amount of granular Hydrogarnet. A homogeneous and densified microstructure was obtained in the aerated concretes with negligible amount of clay after the hydro-thermal reaction in the mixture.