Abstract: In this paper we investigated the influences of a spherical catalyst with δ-function activity profiles on the maerokinetic behaviors of a first-order series reaction. First we solved the dimensionless mass transfer differential equations according to different activity profiles and their boundary conditions. Next we obtained analytical solutions which involve the concentration profiles of each component in the catalyst, the effectiveness factor of the first step reaction, and the selectivity of the intermediate product B. Finally we established some valuable results for analyzing deactivation kinetics and for designing optimum activity profiles of catalysts.