Using effective field theory with a probability distribution technique, the magnetic properties in an infinite superlattice consisting of two different ferromagnets are studied in a spin-one Ising model. The dependence of the Curie temperature is calculated as a function of the thickness of the two slabs in one period and as a function of the intra- and interlayer exchange interactions. A critical value of the exchange reduced interaction, above which the interface magnetism appears, is found.