Introduce the principle of magneto-optical recording and substrate materials of magneto-optical disk, specifically the properties,manufscture methods and protective film of the rare earth-transition metal(RE-TM)alloy amorphous film.And simply describes the properties and feature of oxide single-crystal,multi-crystal and multiple-story magneto-optical recording film. It is pointed out that the future developing tendency will be multi-layes magneto-optical recording materials.