Abstract: Microstructure,differential thermal analysis, mineralogical and chemical component analysis was performed on municipal solid waste incineration fly ash, which was used to make ceramic brick together with yellow ceramic clay, ripe sand and feldspar. Besides, mineralogical component, phase transformation and `leaching toxicity were analyzed on ceramic bricks made according to the optimum proportion. It is found that main mineralogical components of fly ash are calcium silicates and alumino-silicates, and that it registers as a SiO₂ – Al₂O₃ – metal oxides system, which can be used as a raw material of ceramic brick. Fly ash contains particles resembling glass bead and over 50% glass phase. Fly ash shows great activity when temperature exceeds 1241 ℃. Major mineralogical components of ceramic bricks are quartze, mullite, cordierite, andradite, enstatite and wollastonite. Content of crystal phase first increases and then decreases with increase of sintering temperature, while that of glass phase registers a reverse tread. In addition, leaching ratios of heavy metals in the sintered bricks are substantially reduced compared with those in green bodies of brick, which are below the limit value for hazardous waste.