Containing more SO3 and f-CaO, the fluidized bed combustion (FBC) ash and slag is easier to be in greater volume expansion when it is cured in the normal temperature. The linear expansion rates and the strength development of two FBC ashes and one FBC slag in autoclaved curing and normal curing are studied, and the hydrated products are also analyzed by X-ray diffraction (XRD) and SEM. It is shown that the expansion of FBC ashes is significantly inhibited by autoclaved curing. Also, there is no gypsum and ettringite but some tobermorite in the hydrated products which become richer and better crystallization,resuleing in the significant increase of the sevength.