The invention provides a method for settling large- area amorphous nanocrystalline alloying layer with unipolar anionic plasma, which is suited for preparation of modified layer on surface construction property (corrosion resistance and wearing resistance) and surface physical property for metal and alloy surface. The method is characterized in that: it takes unipolar anionic glow sputtering devcie and method, cathodic voltage: 300- 650 V, Ar gas pressure: 20- 45 Pa; it takes metal target as cathode when used for non-metal, cathode voltage: 300- 650 V, Ar gas pressure: 20- 45 Pa; the vertical space between non- metal material and target material is 30- 40 mm. The invention provides a new material and process for amorphous film preparation.