The statistical theory of Type I antiferromagnetism of Ising spin 1/2 with the nearest neighbor interaction-J on a face centered cubic lattice has been treated by the method of series expansion. The degeneracy of the ground state is eliminated by introducing a next nearest neighbor interaction ～0+. The free energy function for the lower temperature ordered state is written in a series of exp(-4J/kT) and that for the higher temperature disorder state in a series of tanh (J/kT). Using Pade approximants, we have shown that the free energy curves of the two states cross at Tc = 1.74J/k, which clearly indicates the transition is of the first-order. The related physical quantities such as the long- and short-range order parameter, the internal energy, the entropy, the specific heat as well as the magnetic susceptibility were calculated following the variation of temperature. They all change abruptly at Tc and the latent heat Q = Tc△S = 0.44J. It is-proved that the theory of AB alloy superlattice, typically such as CuAul, may be for-mulated with its free energy similar to that of type I antife rromagnetism. Consequently, the characteristics of the transition and the physical quantities obtained can be naturally applied to the superlattice problem. We have shown analytically that the Tc- H curve exhibits a maximum at H=0.
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