A preparation method of a conductive via hole structure, a preparation method of an array substrate and a preparation method of a display device, the preparation method of the array substrate includes: forming a first metal layer (01) including the first metal structure (01a), forming a non-metallic film including a first part corresponding to the first metal structure (01a) and an organic insulating film (40′) in sequence; patterning the organic insulating film (40′) to form a first organic insulating layer via hole (41) corresponding to the first part; then baking to form an organic insulating layer (40); and then, removing the first part of the non-metallic film to form a non-metallic layer and expose the part of the surface (011) of the first metal structure (01a). This method can avoid the metal structure from being seriously oxidized.