Abstract: The nonisothermal effectiveness factor (E. F. ) for reaction with kinetics r = kcm/(1 + Kc)a can be improved by catalysts with nonuniform activity distribution. The optimal distribution function in one-dimensional model with which the E. F. can be maximized is a δ-function which means that the activity of the catalyst should be concentrated on a layer with negligible thickness at a precise location x from the center of pellets. The general equations for predicting the value of x and the maximum E. F. as a function of thermodynamic, kinetic and transport parameters are derived and they can be given explicitly in the case of a = 0, m=a or isothermal reaction. For reactions with positive order kinetics the optimal position of the activity locates on the surface of the pellet in the case of endothermic or weakly exothermic heat of the reactions, and it moves towards the center as the exothermic heat of reaction or the activity energy gets larger. But for negative order or bimolecular Langmuir-Hinshelwood kinetics, it usually locates in the pellets except for severe endothermic or diffusion-control reaction. Both finite thickness of the active layer and a deviation from the optimal location x decrease the value of the E. F. It was shown numerically that the E. F. decreases slightly with an active layer at the inner side of x but seriously at outer side.