The magnetostatically coupled multilayer films (GdFeCo/AlN/TbFeCo) were prepared by sputtering method. The measuring results by vibrating sample magnetometer and Kerr rotation hysteresis loop measurement indicate that the Kerr rotation angle of the readout layer (GdFeCo) at no external field is almost zero, and the magnetization direction of the readout layer is in-plane at 25 ℃; the Kerr rotation angle of the readout layer has a maximal value (0.54) at 125 ℃, the magnetization direction of the readout layer is perpendicular at 125 ℃; the magnetization orientation of the readout changes from in-plane to perpendicular with the raise of the temperature. The magnetization direction of the readout layer changes rapidly from 75 ℃ to 125 ℃. The magnetization mechanism of the films was studied. It was found that the magnetization reorientation of the GdFeCo layer is effected by the saturation magnetization and the effective anisotropy energy, but the transition occurs mainly as a result of the changes in the saturation magnetization. The saturation magnetization and the demagnetizing energy of the GdFeCo layer decrease with increasing temperature, and the transition of the GdFeCo layer from in-plane to perpendicular magnetization occurs. The films are suitable to be used as center aperture detection-magnetically superresolution (CAD-MSR) recording media.