Abstract: Solidification/stabilization operation of the ashes from hospital waste incinerator depends on their physicochemical properties. The characteristics of three ashes samples from different positions in the incinerator were investigated with XRF, XRD, SEM and AAS for their chemical composition, mineralogy, morphology, metal contents and leaching behavior of heavy metals, aiming at finding a safe and efficient disposal method. The results indicated that the bag fly ash (FAl) has high chloride/sulphate content and a feature of loss on ignition (LOI) as well as the alkali metal, and its leached concentrations of Cd, Zn and Pb in FA1 far exceed landfill regulatory thresholds of the hazardous waste and should be pretreated prior to landfilling. The CaSO4 is found very high in the flue ash (FA2) and bottom ash (BA) mainly consists of silicates, and they have low leachability and could be classfied as non-hazardous waste.