This work represents the results of the theoretical study of the distribution of concentration and temperature in porous catalyst, carried out over spherical catalyst pellets for the methane-steam reforming reaction over Ni/MgAl2O4 catalyst. Kinetic information has been taken from a recent study [J. Xu, F.G, Froment, AIChE J. (35) (1989) 88-96] for the above reaction, The mass and heat transfer distribution coupled with chemical reaction, outside and within the catalyst particles for methane-steam reforming reaction was estimated in this present study. A computer program was written to calculate both concentration profile and temperature profile for the methane-steam reforming reaction.