Uniformity of change in catalyst activity during a multi-pulse TAP experiment with porous catalyst was theoretically analyzed for a TAP reactor with the ratio of the catalyst bed thickness to the reactor length of 1/30. The analysis was performed by simulation of an irreversible adsorption process. The catalyst change is described by the change in the occupied/unoccupied fractional surface coverages. The intraparticle uniformity is indicated by a small magnitude of p,max, the maximum difference between the occupied fractional surface coverages at the outermost and the innermost of the catalyst pellet during the multi-pulse experiment. In the interparticle region, the indicating quantity is b,max, the maximum difference between the pellet-outermost fractional surface coverages at the inlet and the outlet of the catalyst bed. It was found that p,max generally depends only on the effectiveness factor in the first pulse experiment, . For 0.94, p,max0.05. In addition, b,max depends only on the gas conversion in the first pulse experiment, X. For X0.7, b,max0.05.