Abstract: In order to know the morphology，composition，and potential hazards of heavy metals of the spent FCC catalysts， three kinds of spent FCC catalyst from two oil refineries have been selected to be the research objects，then morphological characters and elements composition have been analyzed，and environmental risks have been assessed.Compared with the fresh catalysts，the results of the spent FCC catalysts showed that：1）morphological characters and elements composition have been changed；2）XRD pattern showed an amorphous type；3）specific surface area significantly reduced；4）some heavy metals，such as Ni，Cu，Zn，Pb，V，Ba，and As were added to the composition，and the content of the Ni reached 10-3 orders of magnitude.Environmental risks assessment showed that spent FCC catalyst samples did not belong to the hazardous solid waste.While if spent FCC catalysts were disposed by landfill directly，some heavy metals，such as Ni，Zn，Ba，and As will cause certain risks to the environment.

Key words: spent FCC catalysts, heavy metals, solid wastes, environmental risks