Abstract: The attrition of two different fluid catalytic cracking(FCC) catalysts was investigated by laboratory-scale jet-cup test.The mechanical properties of the catalyst particles were evaluated by nano-indentation test and conventional microhardness test based on the nano-and the micro-length scales.The attrition mechanism of the catalyst particles in a gas fluidized bed was analyzed in terms of indentation testing,morphology characterization,attrition rate evaluation and particle size distribution analysis.The influences of material characteristic properties on the particle attrition were mainly discussed.The results show that the attrition of the catalyst particles follows Gwyn's kinetic model and the difference of attrition mechanisms of various catalyst particles can be categorized with the parameters of the Gwyn equation.