The authors present theoretical studies of the magnetization, phase transition and twist angles of a superlattice composed of identical ferromagnetic films with antiferromagnetic coupling at the interfaces. The numerical results show there are some interesting properties of the superlattice. (i) There is a plateau on the magnetization-temperature curve for the period P=4, and the curve has a peak at a definite temperature for P>4 and a suitable external field. (ii) For a given external field and interfacial-coupling parameter the twist angles are sensitive to temperature, and the phase transition temperature from the twist state to the spin-parallel state does not change monotonically with the period of the superlattice. Some of the theoretical results are in agreement with the experimental results qualitatively.