The theoretical and experimental analyses of metal migration for the nonuniformly activated catalysts were carried out. A migration model is developed to quantitatively describe the effect of mobility of the active metals on the change of the active metal distribution in nonuniform catalyst pellets. The experiment of the naphtha reforming reaction was carried out to investigate the migration of Pd over supported Pd-Pt/gamma-Al2O3 catalyst with an eggshell Pd profile. The results indicated that Pd migrated during the reaction and it could be well-described by the migration model. This model can also be applied to Pt migration over an eggshell Pt/gamma-Al2O3 catalyst pellet for tetralin hydrogenation. The mobilities of Pd and Pt in the reaction systems mentioned above are 1.07 x 10(-11) and 3.12 x 10(-9) cm(2)/s, respectively. To demonstrate the utility of the proposed model, the time-varying metal profiles of an eggshell lad catalyst for isoprene-selective hydrogenation were estimated and correlated with the reaction rate constants, and hence, the catalyst deactivation caused by metal migration was estimated.